Re: In hindsight what changes would you do
Only change I would've done. I would've given some scenes some minor time to breathe a bit more. Just a matter of a few minutes. Not even to add scenes, but simply to give the scenes included more space (one minor fuzz I had with the movie was Foley's death, I think it would've come out better had we seen him being rolled of by a Tumbler). But we know that, because of IMAX, the runtime had to clock in at 165 minutes and there wasn't really a way around that.
Other than that... Absolutely nothing! A movie doesn't have to be 1:1 with 'fantasy putting together of the stories' fans do before the release to be enjoyable.