Still, those who dismiss Gingrich as hopelessly unelectable in the general election should at least keep in mind that Gingrich's apostasies will make it harder to tar him as a cookie-cutter "right-wing extremist."
The crucial question for most Republicans will be: Who would govern more conservatively? The candidate who answers that question to the satisfaction of the GOP base will likely be the nominee. But that question begs another: What will Congress look like?
If the Republicans take back the Senate and hold the House, you could make the case that Romney is the better man for the job. Given his unpopularity with the base of his own party, he would be on a much shorter leash and be expected to fly Ryan's flag over the West Wing while making Republican proposals seem more reasonable to the public. He very well might be the technocrat in chief, implementing reforms not necessarily of his own choosing.
Gingrich, meanwhile, is much more of a wild card. It's no secret he sees himself as a world historical figure, the last of the great statesmen. And part of that self-conception is his idea that statesmen cut grand bargains with the opposition when history calls for it. That's not necessarily a bad thing, if you know for sure when history calls for it. If the GOP controlled Congress, conservatives would be on constant "Nixon to China" watch with a President Gingrich.
Given the craziness of the season, I've been humbled enough to say I have no idea how this will play out. But I will admit, I'm looking forward to the next steel cage match.