I like the fighting style in the game, but what I think they should do is make an adventure/(maybe a small mixture of platforming elements) game based on the show...... or maybe even developing new plots and throwing them in as well.
I kind of liked the graphics on Budokai, but cell shading could be cool too. I think that it should include some RPG elements. When ever you run into a villain, you would go into a battle resembling that of Budokai. The battles would only be different if it wasn't a main villain but a henchman, like the saiba men, and if you're stronger than them, you will have an advantage
Example: Like how they get faster as their strength increases. if it's just a henchman, they will move in slow motion, giving you the speed advantage....... I think that is better than making you fight really fast.
I could see a lot of potential in a game like this, if they took the time. I'd definitely have fun playing something like that, and I'd definitely buy it as soon as it hit the shelf........ even though I am kind of losing my interest in the show.