Won't 64-bit Wine still be able to run 32-bit programs as well? To my knowledge that was the end result of the whole "continuing 32-bit support on Linux" announcement (which they sort of backtracked on and reworded), although maybe it's different specifically for Wine, I dunno.
I've always liked sticking with 32-bit because 64-bit is overkill and the latter systems have always been able to run the former anyway, making it easier to manage all my projects. Once there are multiple distributions things get really annoying and error-prone. I'd have to update a lot of stuff just to be able to add 64-bit support :/