All good points. I want to add emphasis to the storytelling aspect of it all, though. Lucas and co. trying to outdo each previous installment is fine, in theory. As Stan Winston said (of Terminator 2), "A sequel must be true to the original, but must be MORE than the original". I think KOTCS (and LC, for that matter) lose focus and forget that first part at times, of "being true". Being true to your established characters isn't just recreating scenes (LC is very guilty of this), nor redoing things on the surface, but trying to recreate WHY they became great.
I think that, if anything, is the biggest problem with KOTCS. It just doesn't "build" in a proper storytelling sense. It's a Frankenstein script, stitched together from many different pieces of many earlier drafts. Then again, Raiders was just a series of cliffhangers. But Raiders had several good elements holding it together like glue, in particular, everyone's REACTION to the Mcguffin, the Ark. KOTCS needed a build-up of dread as to what they'd actually find. To paraphrase X-Files, don't open the doors of the cosmos unless you're prepared to deal with what is behind them.
KOTCS could have benefited greatly from a greater sense of dread, fear, or at least wonder about the crystal skull itself, and what it would lead to. Indy and co. just seemed to treat it like a trophy or a football. Spalko, at least, talked about what to expect. In the tent, for example, when she speaks about what they may find, I was getting creeped out, and that's all to the good. Should have been more build-up like that.
Or, for instance, the Ring in Lord of the Rings. It's how everyone reacts to it that matters. And you see evidence of what it's done, to people, to places, etc. If we saw more evidence of the crystal skull's effects on people and places throughout the film, and the heroes were savvy enough to connect them, and start to fear where they were going, I think a much greater percentage of the audience would have liked the alien revelation at the end.
