The scariest voice for Social Conservatism, because he has a natural charm. I think he would've done better than McCain due to economic populism, though I also think the Republican brand was too badly damaged in 08 for any Pubbie to win.
This.
Before he announced he wasn't running, he was leading in most 2012 polls as well, and had the best chance of winning out of any republican.
That is just simply not the case.
In the 2011 polling that included him, I did a comparison and only state where he did better than Romney against Obama was NC, which Romney ended up winning in the end. Amongst the other states, Romney generally had numbers in line with his position nationally in most of those states and in more then enough to win the EC, whereas Huckabee wouldn't have had enough states within a reasonable range of the national PV to come close to winning the EC. It would be fair to say that Romney blew his comparative advantage over Huckabee throughout 2012 through mistakes and gaffes, were it not for one thing. Todd Akin.
Huckabee was the only one who stood by Akin, and what his worse, he blew off a similar incident back in the 1990's with someone else and then appointed that same guy who made a similar comment to a position dealing with matters of healthcare. Obama would have not only wrapped the Akin scandle right around Huckabee's neck, but strangled him with it.
Both from the perspective of 2011 and in hindsight, there is no way to square a claim that Huckabee would have done better then Romney with the facts presently available to either perspective.