Well - and this is going to sound so obvious people will probably argue with it, but I'll hold to it - what's the most important thing to establish visually in an action sequence where the jeopardy is 'a huge aircraft is falling out of the sky?'
You do a top down shot of whatever the aircraft is over, right? You want the audience to know (at least a little) what it's going to crash into when it falls, both so we're aware of the reality of The Ground as an approaching deadline, and so we can worry about the helicarrier crushing little houses/people/fishes/whatever. You only need one quick shot to do this. But instead the shots we get during this sequence generally depict CGI cloudscape; there's not even a ticking altimeter shot to build tension.
These are cliches, of course, but they work! Film uses visual language to tell stories!
From a script standpoint I'd also question the necessity of saving the helicarrier at all - I think the heroes need to fail as punishment for their disunity and proof of Loki's menace, and SHIELD needs to be taken mostly out of the story for the remainder of the movie (they are anyway, but with much less justification). But that's a separate class of issue.
