If you ask me the best choice to make a Mario movie would've been Aardman - they work wonders with silent characters and Mario characters aren't particularly known for their diction. Plus most Mario characters (sans the princesses) already look quite like Aardman characters as is with their big noses and ears - it'd be pretty cute to see the princesses temporarily redesigned in a style closer to Mario and Luigi. Aardman's British flair could also bring Mario back to his Wonderlandian roots.
Meanwhile I'm just sitting here and wondering what all of Activision's devs are up to. Besides Tony Hawk.