At the moment there's the standard game mode where you fight the first to win x many rounds, the practice mode where you fight a static opponent and versus mode.

What's needed to complete the set is a mode where you select your fighter and your opponent (like practice), but where the computer fights you, and you fight rounds- perhaps indefinitely. This way you get to practice against characters you're weak against, or just want to fight against for whatever reason, without going through the standard mode with your fingers crossed. You'd also get to set your opponent's difficulty level. - i know you can do this in standard mode, but the opponents get gradually harder there.

They could also stick in a comp vs comp mode but this is fairly pointless- seems like it shouldn't be too hard to do though- so why not?