for me, alpha 3 without using the infinites is the prefect (at least the best) sf game. it has both the fundamental footsies and patient aspect of a sf game and crazy custom combos and juggles that are cool to look at and quite hard to do. most importantly, the game is not slow like sf4.
imo there are too many flaws and stupidity in sf4 to even be considered a be prefect fighting game. the only thing it did well is got a lot of people back into the genre and sold lots of copies. and it was the first one with a functional online play.
the problem is these people that got into fg because of sf4 only know how to play sf4 but pretty much refuses to try other fighters because they dont want to learn, lose once and immediately go back to their comfort zone.
the sad thing is most people that got into the genre dont even bother to try the fgs in the golden era of cvs2, 3rd strike, mvc2, even st (or the dark era depending on what perspective) even with the re-release on xbox live and psn (bear in mind most of them are also available on ggpo for free), because they think these games are too old and hard so the community isnt really expending.
it is very sad to see because sf4 probably has the most tamed and restricted engine out of all popular fighting game.