Of course there are many great aggressive players here, and in the US but I believe that for most players the conservative approach is best for this game.
That's the real difference between American and Japanese players I think. They put in the work to get the execution 100%, even the weak players yet instead of focusing on HITTING the combo, they are focusing on setting it up. You really have to squeeze out every little opportunity that they give you, and the windows are quite small. If you're facing a guy that's trying to "hit the combo" he is much easier to damage in this game, and the tradeoff is relatively small.
SFIV to me seems like a very turtle friendly game, and I think we Americans have to change up a little bit because gone are the days of jump parry/air blocking and things of that nature. The Cali OG's knew that aggressive turtling was the strong style for CE, Hyper etc. They knew that Jumping in is generally suicide. the SFIV system gives you very little room to be a rushdown specialist, and the punishes here are some of the worst in street fighter history. (One bad jump in against Ryu will get you LP shoryu'd SADC xx Ultra for ~40%, Sagat can also tiger uppercut, 2 hitter kick and a fireball.)
Let me know what you think.