Re: X-MEN: Days Of Future Past (Casting, Rumors, Pics till release)
Others have already pointed this out, but the reason Mystique doesn't wear clothes all the time is dealt with in FC, and is actually at the heart of why she joined forces with Magneto in the first place; it's also directly tied in with what she says to Nightcrawler in X2.
With regards to FC Mystique being different from X-Trilogy Mystique, I've never understood why people put so much focus on this because it ultimately comes down to influence. By the time of the X-Trilogy (assuming they take place in the late 90s/early 2000s), she's spent at least 40 years (if not longer) at Magneto's side; it's kind of inevitable that she'd be significantly different, attitude-wise, than the young woman she was growing up with Xavier.
Starbuck: We're all friendlies. So, let's just... be friendly.
"There is no 'supposed to be.' It's an adaptation, a word that literally means change. Why bother making a new version if it doesn't offer a fresh approach?" - Christopher L. Bennett