I'm desperately trying not to think of Leslie Bibb in the first one, because I think I'll cry if that's all Kate is. BUT it does give me hope that, for now, her role is "secret" (which can either mean 'ZOMFG cool!' or 'it's not even worth bothering to tell you') and she was announced the same time they announced that Agent Coulson was returning.

You know, it's the same thing as the Kirsten and Bryce effect in Spider-Man 3: they got two famous blondes and made them redheads, now they've hired a redhead and they might possibly make her a blonde? Hollywood's kinda wacky that way!