Theres actually a SFIV cab around my area, i havent played it yet being 75 cents and i have alot studies...but i do eventually plan to play it too. The game is actually out in the states in limited quantities and locations for a while already.
I seen matches being played before and its definitely different from the original SFII but it still retains its essence from it as well as the Alpha games. The backgrounds are totally new, 3-D cel shaded and rendered, and if anything the only thing that looks like an updated old stage is Guile's and Chun's 3S stage. The rest like under the bridge, Seth's stage, and the boat with the sunset in the back are totally new along with the Vegas looking one.
Besides no one really cares about story. Its just an interesting side tibet for most people(and if in shoryuken.com would be a flamefest lol). The main meat of the game and the reason why the original ST game lasted so long was because of the gameplay and how the things were structured. Have you seen the story of the original? It sucked ALOT. But no one gives a damn thats not why they play it.
In the end, thats the reason why theres alot of different versions of SFII because the gameplay has changed and things have been tweaked to turn it into an entirely different game(if you want to think about it differently you can think of the different versions of SFII to be patches or new expansion packs to an MMO or online game). Theres no need for backgrounds to be different totally or story to make it a good game, its just an added bonus unlike RPGs where everything is about the story and without it, it would have suckass gameplay.
So i think you are looking at Street Fighter the wrong way when you want a new game. Try playing more people that are better than you, then learn more about the game...then find even harder opponents. You will learn so much that it becomes second nature to play it if you put in the effort, and that the mechanics even upon looking at gameplay is very different from all previous games yet still remotely familiar. Its a competitive game and should be treated as such once they added a 2P function, not an RPG.