One thing i like to wonder is, why are people bashing the SFII line? SFII and Turbo were yes kinda retarded in that the only difference was bosses and speed. However to me it does make alot of sense why SFII is the same. Street Fighter II was the start of defining the fighting game engine, and back then when not even Fatal Fury or KoF matched up to SFII(they were copies that just wanted money on some fad). They were defining the role of fighting games. And i think were establishing what is a "good fighting game". So of course theres going to be alot of rehashes, but there were alot of little fixes that made the game move forward that people who dont play deeply into these games not appreciate and know.

SFII started by giving more different variety of fighters that are more unique than the Ryu Ken choice in SF1. Speed was a big issue in how intense the game is, as well as touched up deeper gameplay(remember SF1? that was crap gameplay), then they added a Super Bar in Super SFII Turbo. Testing out what happened to spice things up if they added a super bar. Then SFA series came out with revamped Supers and added alot more balancing the health with it(as the SFII series did not). Then different super bars. Now SFIII is testing out what happens if everyone can block all your moves if predicted and testing out the value of only having 1 super(and therefore many different versions of the same character with different supers and how to link into it as its different link per super).

So while to the people who dont play the games that deeply wont see any difference but minor changes, i think it came a long way into establishing what a fighting game is, as well as experimenting different things while putting it high into tournament play. Almost all SF games are tournament worthy.