Great work, Eric.
I'm going to be a bit of a skeptic here. Hopefully, this is useful insofar as others can prove me wrong in order to sharpen the argument here. If you can't prove me wrong, but have something to add, go ahead and reply to me off-the-list, because I don't want to distract from the actual advocacy purpose of this list.
I would like to be able to embrace this argument — that approval voting would help Republicans nominate better candidates. And clearly I do think that it would help them in the long term. But I'm not sure I can see how it could have helped them in the previous election. The dynamics I saw on the R side last time were a series of flash-in-the-pan "not Romney" candidates coming to the fore and then burning out due to clear negatives. I forget the order, but I can remember at least Perry, Cain, Bachman, Gingrich... With approval, the "not Romneys" wouldn't have had to take turns so much, but how would that have helped overall? The only answer to that question which makes any sense to me is "Hunstman".... and honestly, while I personally see Hunstman as not as bad as Romney, I see no a priori reason to think that the former would have done better than the latter against Obama. In particular, if you go back in time to 2011, why would I believe that Huntsman is "more centrist" than Romney?
Jameson