My theory for Street Fighter IV's undeservedly high scores: the average age of reviewers now were heavy street fighter arcade users back in the day, and are simply paying homage. To them, all Capcom had to do was remake it in HD. To everyone else, this is just a fighting game, albeit a quite rewarding one. 10/10 does not take into account the average gamer.
Street fighter and veteran of all fighting games in general here. Difficulty on this seems way way off. First run through i was owning face like usual until the last boss which i could not beat after many tries. I then stepped it down to the easiest difficulty just to screw around...only to start getting beat on the earlier fights. I had to go back just to make sure i didnt increase it. The cpu was fighting waaaaaay better than when i was on hard difficulty. WTF?!