Walker and Pence at the at top of my list, along with Cruz. I definitely want to see Walker on the stump before getting on board. Running for president is about media performance first and foremost.
I would prefer a cool-headed President with a proven administrative record like Pence with a rhetorical master like Cruz taking as Senate Majority Leader.
Walker is a non-starter with me. Although he is courageous and principled, he's an open borders guy compared to Pence.