Ike looks awesome.
In terms of females, Nintendo could easily pluck a few from the Warioware franchise. Ashley, Mona, and Kat & Ana all come to mind... give Ashley magic based attacks, or Kat & Ana an Ice-Climbers-like melee attack repetoire, and you're set. From FE, it'd be great to see Lin IMO. And also Nintendo could go ahead and get Daisy and Midna from their catalog too.
I'm still waiting for Geno and Little Mac.
Pit HAD been my previous most wanted addition, and I'm thrilled to see his inclusion, but now I'm greedy.