I don't think she's changed that much. She still smiles and is goofy, but I think she's just gotten over the honeymoon phase with the business and now she realizes that it leaves the seat up and farts in bed kinda phase.
I do wish she'd do another action movie, but a modern one. Something along the lines of Domino, but obviously not the same thing. I just like seeing her angry and kicking butt. Makes for great work out movies. She does just meld into period pieces though... *le sigh*
I love the hair for The Dutchess. It looks incredibly annoying to keep up, but it's gotta be fun just walking around with a big old poof of hair on your head. The dress is devine as well.