You know, I think I would not be interested in seeing a Civil War adaptation. Sure, okay, the issues of security vs. freedom are worth exploring in this day and age, but I really have seen enough of heroes fighting heroes. I can buy the idea of heroes initially being at odds due to a misunderstanding or difference of priorities, but ultimately their shared commitment to heroic principles should enable them to move beyond that and realize they need to work together. What was cool about The Avengers wasn't, for instance, seeing Tony and Steve bickering; it was seeing them instantly put their differences aside and work together the moment danger struck and lives were at stake.
And I agree, it really is hard to see Tony Stark buying into the government's pro-registration line, especially in the extremes to which it was taken. That felt out of character to me. I recall there was a lot of inconsistent characterization in and around the Civil War event due to all the different writers not being on the same page. It seemed that characters were forced into actions and attitudes that they'd be unlikely to support just in order to drive the story. That's not something I want to see in the movies.
From what i remember about it Stark thought he would be best to control it from within to curtail the more extreme calls for measure, it was about the same reasoning Reed Richards had for joining the Pro-Registration camp (including directly borrowing from Asimovs Foundation with Psychohistory.. though i have lost track on how that storyline progressed).
Now obviously having heroes become defacto villains will lead to out of character behaviour and thus the whole storyline was flawed from the beginning but nevertheless i found it to be an exciting read and some one shots or side-storylines were truly great (i remember one issue where shortly before it really heats up Cap and Steve meet in the destroyed Avengers Mansion to try to find common ground and remembering the good old days) but what was best for me was the public discussion about the general theme of it.
You could easily discern where someone stood in real life on very important real life issues like civil rights, moral rights, law and the general state of society and that for that Civil War was a very good mirror for us (even if the execution was flawed).
I'm very curious to see how the movie develops and what comes out of the concerns Cap has about Shield (he already got a first glimpse in Avengers when he alongside Tony Stark uncovered the secret project). I have said it already but this is what is great about the Captain America character.. he is just so painfully black and white.. he doesn't do compromise on essential issues for the greater good. If something is wrong it is wrong.. period and you won't change his mind or even soften him uo.
I hope this comes through in the movie and it won't be a simple slugfest between him and the Winter Soldier (though them going hand to hand in the trailer was pure awesome!).