Alright, guess I'll get these thoughts out. I'm going to start with the 2v2 maps and order them from most standard to most bizarre/broken. When I can. I'll also be speaking from the perspective of "high" master (top 1-2% of the playerbase) play in each team league. It should still be relatable information to anyone below that, but it will seem increasingly less true the further away you are. I'm also going to make the assumption that both teams are absolutely equal at all times unless I state otherwise. If the two teams' armies clash in the middle of the map, it would be a draw. That's never going to be the case but it's important to draw any conclusions about the map's design.Scorched Haven
This map has been in the map pool since the beta and is pretty much the only one that hasn't failed the test of time, though it hasn't particularly exceeded either. It's somewhat like the metalopolis of 2v2. It's a decently small map, with two fairly close ramps facing inward to expansions for both players. That's really all it is, though. The rest of the map is almost irrelevant. The outward third base in the corner of the map is surprisingly defensible if you can keep it alive long enough to where you can get some cannons/spines/pfs. If you can get enough defenses to where only a large army movement is capable of killing it, any attack your opponent might make towards it puts them in a exploitable position. Even if they manage to kill the expansion, as long as you can out maneuver their army to force a favorable engagement you can make them pay for it or even outright win. All of the expansions down the center of the map only exist to starve your opponent if they're turtling. I wouldn't recommend ever taking them unless you're going for an economic win and you know you can't break your opponent... or if you're just screwing around. They're far too vulnerable in a close game.
The natural looks inviting but holding the area below your ramp isn't as easy as it might look. The choke is just a little too wide, and the attack distance is just a little too short. This means that any sort of early one base attack that can cut off one of the ramps is powerful (forcefield for instance). It also means that any expansion before, say, 6 minutes can be suicidal. This is pretty much true of most team games on all maps. You need to be able to defend a quick rush, and assuming your opponents don't rush, you need to be able to put on pressure in case they decide to expand too early themselves. It's just the nature of it.
Some people decide to do a wall-off between the ramps to secure their natural right away. It can work but you'll lose to some relatively common rushes like a 6 pool. The choke is too wide to get enough units out to defend while making a full wall. I feel it's too risky and not terribly rewarding, as your opponent can just expand sans the defense you had to make.
Other than that the map is really standard and simple, no strategy works better or worse on it and nothing really stands out.Molten Crater
This map is very similar to Scorched Haven in that it has a main and natural, where the rest of the bases on the map are primarily for starving your opponent and winning an economic game. The difference is that the natural is considerably more defensible. Not only is the choke much smaller (and longer), not only is the map larger, but even the area around the natural is much smaller as well. This is one of two maps in the entire pool of team games where you can consider fast expanding. You can even do a basic 1v1 FFE on this map. Some people might try to metagame that aspect of it and have a nice one base cheese awaiting you though, and it'll probably involve those cliffs that I'll mention.
Turtling on the main and natural on this map is extremely effective. Moving into the main choke with a large army during the mid/late game, when splash damage is copious, can be suicidal. This makes the cliffs along the main considerably more vulnerable terrain than the main entrance, which is pretty unusual for most maps. Until the game advances beyond the main and natural, things such as: drops, banshees, blink stalkers, muta, floating buildings, tanks along the bottom of the cliff, warp prisms, etc... are all quite powerful. If you're economically focused you'll want to put most of your defenses and awareness along your cliff more so than the main choke.
Once your natural is secure you'll want to move out to take the gold expansion next, but you'll note how very exposed it is relative to your natural. Generally games are won and lost at this stage. If you can get your gold expansion up and deny your opponent's, you win. Maybe not always right away, but eventually.
This is the expansion path you should take:
Red means a more vulnerable base, or simply the further away from the main choke means it's more vulnerable to harassment. A lot of people take the expansion I marked with a red dot because it seems more natural for a third, but it's actually very risky and unstable. It has to be a hidden base or you have to be ahead to hold it. It's only a small walk from the opponent's gold, and it's not a very forward expansion that you can defend while pushing.Tyrador Keep
And this is the other map where you can consider fast expanding. If you're confident that one player can hold the ramp, the other player can safely expand. The rocks will hold quite a bit of damage and will buy enough time for the expanding player to catch up in army to defend a rush. The ramp is only a slightly weaker point than the rock entrance if your opponent chooses to rush but it should also be defensible if you can see the attack coming. The other player can take the low ground expansion once the fast expansion starts paying for itself.
There is some rotational symmetry imbalance on this map. When players are trying to take the expansions at the empty spawn point, it favors the team who has rocks nearest the rockless ramp of the neutral high ground. For example, if team (a) spawns on the southern high ground, and team (b) spawns on the eastern high ground, team (a) has the advantage in taking the neutral western high ground (c). This is because not only does movement in that direction coincidentally protect (a)'s gold (with the (b)'s gold fairly vulnerable), and not only is it a relatively short distance from the rocks, but because (b) can't break down the neutral high ground's rocks without a serious army commitment. There should never be a large army commitment over the neutral high ground because it will leave important locations very exposed. You can't have a few units attacking the rocks either, because it'll take too long for those units to be doing something the other team doesn't have to. Unless you're already ahead, it's a good idea to allin as (b) if the game gets to the point where the neutral bases come into play.
You'll also note that the map isn't even entirely rotationally symmetric either. The distance from (c) to (b) is a lot further than (a) to (c). (a) > (b) > (c), though (a) < (c) if they're both occupied. I wouldn't mention any of this if it hadn't lost me games.
The only other thing to mention about this map is that the high ground natural's mineral line is very exposed. It can be fungal'd and sieged and so forth. There's not much you can do to defend it other than to be ultra aware though. I say it as more of something you can take advantage of.Magma Core
I'm unsure about this map. The obvious natural is very exposed and hard to take right away, making it very one-base oriented to start. But once the natural has been taken and secured, it protects the ramp for you to take the expansions in your other possible spawn location. You can take them almost for free, which turns the game into a very turtly macro game.
It's also kind of hard to break the other team if they're on one base since they're so close to each other and share the ramp. So the crux of this map comes down to denying the natural and taking yours first. From there, it's macroing, defending, and picking the right time and place to fight. If you can take and secure either gold, you win. It's... kind of dull.
The cliffs marked in red are vulnerable. There's not much else to say about this map. It's not a bad map but it makes for bad gameplay in my opinion.Desolate Stronghold
This map is about 30% too big. It takes a while to travel from base to base, which makes expanding favorable... but then the expansion is very open, which cancels it out. When I play on this map I feel like I'm traveling between islands. I have the island that is my main, the island that is my ramp, the island that is my natural or other expansion, and then the similar islands of the opponents'. Everything in between is a sea of nothing that is suffocating me while I struggle to make sure that I have enough on each island. It's definitely different.
Everything that does area control is weaker because you can always move around it: siege tanks, defensive structures, anything slow. Then everything that is fast and benefits from flanking is stronger: bio, zerglings, zealots, etc.
Expanding on this map spreads you very thin, but it's something you will need to do most of the time. What expansions you decide to take depends on what strategies are chosen. If your opponents have drops or air, you might want to expand very close to your ally. If you're going ling+muta, you might want to expand in the corner to make your opponent commit to either your expansion or your main ramp, given that they're so far apart by ground but close by air.
This map is playable but it feels wrong to me. I'd veto it but there's definitely worse...
Here's the three that I veto.Lunar Colony V
There's only two things you need to know about this map.
The first thing is to not expand at the 3 and 9 o'clock positions. It feels like it should be the second base your team should take after the natural, but it spreads your armies too thin and doesn't give you much to work with as far as a staging ground or future expansions.
As you can see, if you take (4) instead of (2), you have a much larger area that you have to keep protected. For instance, if you have your whole army at (4) because of a drop, and they come in to attack your ally's natural (1), your allies army or expansion could be mostly dead before you can reposition to help defend. Likewise if some lings run into (1) and they all attack at (4). All it takes is one moment where you're out of position for you to lose. Also, if you take (2) instead of (4), (3) and (5) suddenly look a lot easier to take, whereas (4) is always going to feel like a liability. It's true that it'll protect your main from drops, but just put a couple defenses down and you're fine. Hell, even if they attack (2) from the further ramp, there's that nice choke, LoS blocker, and vespene gas position that makes it difficult to attack into.
The second thing is that the majority of what I just said is largely irrelevant because you can't take your natural unless you contain your opponent. The natural on this map is the hardest to hold of any map I've covered so far. It's too open, and it's too easy to get between the natural and the ramp, cutting off anything attempting to defend the natural. If you stay on one base and your opponent expands, and you put the money they spent on the expansion into one siege tank, you need only get that one tank in range of their ramp to kill the natural. Not that that is the only way to do it... Just about anything works, but for different reasons which you can't premeditate with any certainty. That's why I veto these three maps, the best way to win is to do a one base allin and pray.The Boneyard
aka Even Smaller Delta Quadrant
Pick a one base allin. That's basically all this is. If you do a strong timing with your ally you'll probably win, but sometimes not. Why? The map is too small to react to anything. It takes less than 20 seconds to travel from ramp to ramp. All you need is a way to break up the ramp, and there's so many different ways to do it that require different reactions to defend. You can't prepare for everything, so the only thing that makes sense is to always be the aggressor. The expansion in the back is quite safe, indeed the only safe expansion, but put too much money into it and you can die to a strong push. Or not. Roll the dice.The Ruins of Tarsonis
Yeah, this one is worse. I think this is the worst map in the entire map pool for all leagues. The only other map that might be worse is Frontier (3v3, I'll cover it), but the reason I think this is worse is because it's making me angry just looking at it. Those "natural" expansions, those gold bases, the LoS blockers, that little slit that lets smaller units travel from the two expansions outside the main, the weird low ground between the mains, the watch towers that give vision over everything but the only important attack path. Someone got paid to make this garbage. And it has been in the map pool for over a year... I need to stop facepalming to finish this post.
Anyway... Terran dominates this map. 1-1-1 is unstoppable. Siege tanks can go from a very defensive position to assaulting your base in just a few seconds. There's no delaying it, no counter attacking, no cutting off reinforcements. You just die unless you're also terran and are doing the same thing.
The expansion behind the ramp blocked with rocks is your real natural if you're not terran. But if you're expanding and the enemy team has more terrans than you... I don't know what you're hoping to accomplish. You're already dead. If you happen to get double terran yourself and build siege tanks, congratulations. If there are no terrans, it's still an awful map. I'd rather play on steppes of war.
So, that's the 2v2 map pool. I've included some replays that help illustrate my points. Some of them are decent games. I'll do both 3v3 and 4v4 a little later. There's not much to say about the 4v4 maps because they're so variable but there's a few things I can point out.