Well, i would certainly like to see integration with Playmaker... Unity's legacy animation system has been a bit troublesome for me and i'm taking some time to try and learn mecanim in the hopes that i'll be able to address that.
but, that being said, being able to wire it together with playmaker (such as telling it to set the various animation parameters) would certainly be something i'd like to see be a bit of a priority and given that one can easily (from what i've been reading, haven't tried it yet) transfer animation data from one character to another.
so, yeah, i'd certainly like to see it integrated also