Absent anyone being able to convince Dick Cheney to run (Slogan: “The World is Evil. America Needs a Mean Bastard”),
First screen on my list: Candidate must have been a Governor. Anyone who has only been a member of the D.C debating club needs to go home and show they can run something besides their pie hole before applying for the big job.
That said, I like Walker- he fights, understands that $$$ are the political center of gravity, and that killing the public unions is the defeat mechanism for the left.