Yes it was only about a year, but to be fair, theres plenty of games that did that even back in the days. For example Capcom vs SNK 1 came out 2000 but in about a year Capcom vs SNK 2 came out, and it was vastly superior. SFII to CE was also about the same time frame.
I think we should really ask, was the difference between the two games in that one year big enough and deep enough to fix all the errors in the first game? In CvS1 - CvS2 i think so and SFIV - SSFIV maybe, but not for games like MvC3 and UMvC3. With the advent of patching, as long as the changes are not big enough, then there should be no reason to release another version of the game within the same year. -_-
Air blocking was strictly an Alpha thing. I think they really made that clear when only C Groove (the most Alpha-esque Groove) can do it in CvS2, and no other Groove. I am personally not sure if it would have been a good addition to the already slow and defensive style of SFIV. I do miss it though.
I also agree that the Focus system is not as good as the Parry system. It was much less skillful to produce results and destroys the zoning game for certain characters. At least with Parry, I feel like i done it myself instead of letting the system do it for me.
I actually hated that game when it came out, but with SFxT and stuff i must say the SFIII series were way better games. Freaking Auto Combos, 12 Char DLCs ON DISC, DLC gems, DLC auto combos...just DLCs in general. By the time you pay for everything you already paid for half a console. The $@^% man?Street Fighter III is the best one.
That is all.
I liked it enough to replay it several times, but it wasn't as good as I was hoping it would be. I think the first one is better in pretty much every area but combat (my only complaint here is that mages no longer have GIANT FIRE TORNADOES). I bought it for about $25 and I feel it's worth about that much to me. The characters are really great, but nobody can replace Morrigan and Alistair. I always liked having them both in my party because they balance each other out so well and plot-wise it's like having a little shoulder angel and devil.
One other thing I do like is the Mass Effect style conversation wheel, but with no reputation system. You get to mix and match!
Unrelated, best Street Fighter game was Alpha II.