Tsukamoto replies on the Street Fighter IV blog the replay channel, second ultra combo, and a completely new character were staff highlights. The replay channel, Tsukamoto believes, can be enjoyed similarly to watching TV. Implementing the second ultra combo gives old characters new styles of play. While the team had a lot of characters (supposedly from past Street Fighter games) they wanted to add, they really wanted a brand new character. And that’s how Juri got into the game.
Tsukamoto also comments on lag issues saying Super Street Fighter IV has a system that will only search for good connections when using arcade requests and quick match. The team is trying to reduce wait time and may add a sound to let players know when someone enters their room.
And if you’re using a standard definition TV here’s more good news. Super Street Fighter IV will have larger text, which should make the game more legible on SDTVs than Street Fighter IV.