If Perry entered the race, it would be an earthquake. He would be a taller version of Mitch Daniels with hair. In other words, he would have the record of an effective governor but with television presence. Perry's baggage is less toxic than Romney's, and Perry would probably easily take the lead over Romney, Pawlenty, and Huntsman in the the former governor's category.
I think if Daniels doesn't enter the race, there will be an effort to draft Perry.
The MSM would try to tar Perry as "Bush's Lt Governor", but I don't know if that would stick.
Sadly, I don’t think Mitch Daniels is viable for the simple reason that short and bald does not sell. Perry has Romney’s looks without the other baggage.