All in all he'd probably make a decent president of the United States, IF:
1. Congress is certain of having a 51% Democratic majority in the House and a 61% Democratic majority in the Senate;
2. He's lying about his foxhole conversion to extreme right wing positions; and
3. No Supreme Court justice outside the extreme right wing faction (i.e. Roberts, Thomas, Alito, Scalia, plus, part of the time, Kennedy) retires before 2020. Several of the moderate justices are quite old, however.
#1 because, like school teachers who teach to the middle of the class, whatever that is, Romney's record is that he weathervanes--within the Republican framework, to be sure--whoever it is whose cooperation he needs to do his job.
#2 because he swears that he's now a right wing extremist, though it doesn't seem convincing to most right wing extremists; but I think we should take people at their word unless it's proven that they're lying, and having taken opposite positions in the past isn't dispositive. Suspicious but not conclusive.
#3 because President Bush II will be President by delegation until his Supreme Court appointees retire or die--possibly up to 30 years or more from now. Doesn't matter what a liberal Congress passes and a Liberal President signs into law if our right wing Supreme Court overturns everything. A Romney presidency with a Republican Congress will extend that delegated extreme right wing rule by another decade or two or three.