Capcom V.P., Christian Svensson, said that they pushed the developers of Street Fighter 4 to add in double blind selection support, but for some reason it didn't make it in, he also commented on how to change the main title track so it doesn't drive you crazy.

Here are Christian's remarks along with a word by Seth about M.U.G.E.N from the Unity Boards.
Can you patch a way to make online matches have double blind character selections?

Sven: Double blind selection is something we beat the team up for ages ago and it just never got done. I've got no real news for you on that front right now but maybe eventually we'll have a solution.

Can you guys do something about the music cycle in SFIV? I am sick of hearing that forsaken song every time I start the game or return to the main menu. — Preston

Sven: Custom music is supported on both PS3 and 360... that's probably your best solution.

What do you think of M.U.G.E.N?

Seth: Using Mugen is technically a violation of our IP, but we're not trying to hunt fans that aren't trying to make money off of them. Certainly a lot of it has made me LOL, like Shin-Tom_Hanks.

Sure sounds like double blind selections will be pushed for again when/if Street Fighter 4 is patched.

And considering SSF2T HD Remix made some changes that were generally well received, like making Fei Long's Flying Kick and Cammy's Hooligan Throw easier to execute, one still would wonder why those changes didn't make it into the game as well, and if they might be patched in the future.