So with what we know of SSF4 so far, here's my observations on game balance:
Sagat deals less, takes more. This is the best change they could have done. This makes Sagat fair now, barring all new characters he is still top tier within the original cast. The fact you cannot trade ultra off DP's already makes Ryu and Sagat such better matchups for everyone. Honestly, I probably ate 75% off non-FADC ultras from these two, and thank god they changed this.
I feel like from the changes I've read so far, the original SF4 tier looks something like this. Sagat and Ryu brought down to Rufus/Boxer/Akuma/Viper/Gief level. Ken and Chun Li could also potentially rise to this tier or the tier below. Rose and Dan rise to the new A tier which is the old B tier of Abel/Honda/Dictator/Fuerte/etc.
In other words, I'm saying calling the S tier the old A tier including S, A tier the new B tier, and so forth.
At least concerning the original cast, I think this could be the most balanced Street Fighter ever.
As for the newcomers. I think Ibuki, Juri, and Makoto are going to be in the top tier, making it the biggest top tier of any SF ever. I think Dudley might become the new Sagat, but a less dominant version of Sagat at the top level of play, I'm hoping. I think Juri and Cody are going to be A tier. I think Hakan and T.Hawk could be A tier or B. tier. I think Adon, Dee Jay, and Guy are going to be bottom with Guile and Claw once again. This is just speculation and opinion based on what I've seen.
Overall I can't fucking wait for April. I am still maining Rufus, and from what I've seen Rufus is going to be even stronger simply because his two worst matchups have been balanced. I also think Rufus will become like the counter pick to Dudley. EX messiah should be able to stop most of his mixup game, depending on whether or not invincibility frames have been nerfed (from what I've seen this isn't confirmed either way) it should be able to stuff swing back blow, and that's huge because most characters are going to have no answer to that whatsoever.
Oh and Team Battle. I've already put together what I feel will be one of if not the best Xbox Live team, and I'll put my Pittsburgh boys up against any team GAF has to offer. Let the games begin in 33 days.