Double QI/TC weekends (get more people to play on weekends)
Ability to activate items ingame (you dont have to go to forums all the time)
Uke needs an upgrade when you fight him
Toribash needs a new trailer on the website

First part, from what I hear anyhow, would "generate too much tc and mess up the economy". Though it would draw more players in, possibly, it would have an impact on the economy. Though double QI weekends, that doesn't sound terrible, I wouldn't mind that. I used to play 100 games a day, did it for like 3 weeks or so, and that would've definitely given me a motivation boost.

While activation in game seems practical, Toribash doesn't really NEED it, but it could be helpful for those that don't care for having to go to the forums.

Uke doesn't really need an upgrade when you fight him, his standard kicklift in aikido fairs well against someone who has almost no clue on how to play this game.

The trailer is kickin' honestly, I can't tell you how many times I've gone and watched it for the hell of it. It's kind of outdated I suppose, so it wouldn't harm anything.