Who would've thought 13 years ago that Mystique would be portrayed by an Academy Award winner? I think Fox didn't expect this either. If Jennifer wasn't as succesfull as she is, Mystique would never be the main female character of the movie.
Still, I like her in the comics. She must be one of the most popular and best female comicbook villains (sadly there aren't too many good and relevant female villains).
The movie makers must really like her. In the movies she has always been one of my favorites, but I do think it's weird that she appeared in more films than Rogue and Storm (not counting that little pseudo-cameo in FC).
In general, most people seem to prefer Rebecca's Mystique, but I think Jennifer's Mystique is a great continuation of the character. It gives the character some well-needed development, instead of only being the 'silent assassin'. What we got in FC was a drastic change: from the bad-ass fighter to a main character that is some what the emotional core of the movie. In DOFP we seem to be getting both, so I'm happy. Oh, and that leg?!!! <3
About the Wolverine: Yukio and Mariko were strong characters in their own right. I love them. The actresses did an astounding job, especially knowing this was their first real roles in a movie.