I read this entire thread, again, from the first post. "Why?" I ask myself.
So, seriously, here are some things I'm curious about:
(1) I always assume that the most fun would involve two evenly-matched human players
(2) Since #1 is not always possible, I would assume that single-player mode is important for many folks?
(3) Are there important (albeit subtle) differences in the AI (across all ____ versions of SF II) for single-player matches?
If I were a fan of SF II, I know that the single-player experience would be an important consideration when evaluating a game. My brother, who has always been obsessed with SF II, prefers playing with humans.
Cook prefers to mash buttons when playing Street Fighter II'.