I really don’t see what advantage Pawlenty has over Romney. Romney is a much better campaigner.
I would be OK with Romney too, but I’d be a little concerned that there are a good number of Republicans who really hate him. McCain is already on thin ice and if Republicans who are disgruntled with him see him pick a VP they really dislike, it might be the last straw for them. I think Romney has more enemies than Pawlenty does.
But he’s also better-known and has important business connections. He probably wouldn’t be a bad choice. It sounds like Pawlenty is more conservative than he is though.