From McCain's short list, Eric Cantor is a minority, young, energetic, well spoken, from a toss-up state and, most importantly, a principled conservative. I would pick him. Pawlenty is also better than Romney, but a boring pick.
Outside the short list, If he's going to go with an old white guy, I would pick Fred Thompson instead of Romney. Off the top of my head, other picks that would be better than Romney are Chris Cox, Mark Sanford, Haley Barbour, Sen. DeMint, Sen. Coburn, and Rep. Pence.
All the off the cuff red meat preferences ignore one over-riding requirement.
Someone has to pass the vetting process.
There are hundreds of potential nominees over the years who did not pass vetting. The Thomas Eagleton affair with McGovern has made vetting an absolute requirement. It takes very little to fail.
Belonging to a whites only club. Sitting on the board of a company implicated in trading with Iran. Outright ownership of some company involved with something controversial. Child support disputes. An enormous number of things can fail vetting.
Odds are pretty good that at any one time 30% of any list, long or short, may fail vetting.
I dont want mccain ruining a conservative. let him pic a rino. it would be fun to see 2 losers beating obama/biden