I had some serious concerns when I saw the previews for this movie. The previews were more of the ToD variety: a sidekick, difficult to identify villians and storylines, tons of wink-wink-nudge-nudge, and, even though they tried to hide it, a heavy reliance on CGA.
Now then. In the original format, Jones movies start with a nice little teaser that lets you know something of what Indy has been up to. In RLA it was the wonderful bit in Central/South America with the gaming-inspired, trap-infested idol site. In LC, it was a flashback-laden story that showed some of where Indy came from in the context of a mini-ep about the Cross of Coronado. Neither of the "even" movies had that--a mishmashed jump into the movie was all we got.
Jones starts out in the first movie as a user--he has his soft side, sure, but he is a user. He likes people okay--good people, obviously, never "bad guys"--but he is a violent geek. He blows stuff up, shoots people, and insults people without necessarily meaning to in order to get what he wants (Captain Kirk as an archaeologist). It is why he must get the crap beat out of him, just as Han Solo does in Star Wars movies--he is a good guy overall, but has some bad parts. He operates solo, only *hiring* people to work with him, until he is eventually--and reluctantly--attached to another person. This person is not a liability, however--it is someone to whom he has a significant tie emotionally, and who has assets of their own to contribute to the quest.
These characteristics were present in the third movie as well, but conspicuously absent in the second and fourth--the sidekicks he is saddled with in ToD/CS have little to contribute and are annoying liabilities. Then, somehow they suddenly contribute something that tips the entire scale, seemingly by luck (a punch here, a chant there, a torch over here). They even rescue Indy, who has haplessly been caught with his pants down in a way that makes you question whether he ever deserved the tough hero title.
The storyline in the "odd" movies was pretty easy to follow--get the Christian artifact. It is powerful, ancient, and would be devastating in the hands of the bad guys. There is one set of bad guys racing against you to get it, and they will sometimes use you and sometimes get ahead of you. In the even movies, however, it was different: Chinese gangsters, Indian royalty, and some mystical cult in the second movie; russians, americans (remember the dropped government storyline?) and south americans (remember them?) in the fourth movie. More on this below.
To make matters worse (my opinion, remember), the storyline of the even movies is completely buried in over-the-top CGA. Lucas and Spielberg themselves admitted that the second movie was focused on effects more than the odd movies, and I think that is clearly the case with the fourth movie as well--the initial entrance to the complex was the most glaring, unbelievable part of the entire movie. The whirling vortex of stone was exciting, I will grant--but it did not belong in this franchise. It is just too much, and makes it all about the effects and drowns out the storyline.
To make things worst of all: I got the repeated feeling, both while the movie was happening (and you must know, I can suspend my disbelief like nobody's business) and in discussion afterward, that this was a farewell movie--not an Indiana Jones movie. It was as if the production and creative team sat in a room and said, 'ya know, Harrison isn't going to do another one of these. What should we do?' Then someone said, "El Dorado!" and someone said "Aliens!" (probably Lucas) and someone said "Russians!" (that was probably Spielberg, I think he is over the whole Nazi thing) and someone said "Government paranoia from the 50's!" and Spielberg said, "We simply MUST get Shia Ladouche in here somehow..." Then no one would compromise, so we got all of that. There were repeated verbal takes to the audience (like Lucas' patented "I've got a bad feeling about this"), and a number of unnecessary commentary-on-society nods (Look at that steampunk-inspired automatic deforestation device! Those russians sure are EVIL!) that just took me out of the whole thing.