I didn't like any of the GP games. The control dynamics are just wierd, and the AI is ridiculous.
The 2010 game is supposed to be really good.
I don't know exactly what you are refering to when you say tou didn't like any of the GP games, so it's kind of hard to respond directly so I'll do so in general turns.
The biggest problem with most bike games is the simple fact that they don't act like bikes. They seem to be dumbed down to try and be accessible and end of playing like crap. They act more like cars then bikes. because of this if you actually know how to ride a bike then it can be hard because you can't try to apply real world bike logic to the games because it won't work.
To date most bike games still have the braking dynamics wrong, the games are rear brake bias, when we know in the real world it should be front brake bias. And they make the brakes far to weak. Additionally they make the bikes insanely unstable when it comes to slow speed turning.
The AI, well what can I say it pretty much sucks as we all know. Unfortunately while car games have moved forward for the most part devs still don't know what to do with bike games because they keep trying to make it a mass market item when it isn't. So they keep tweaking the physics making something that should be smooth and simple, jerky and complex.
When you say "the next one should be good" I hope you aren't referring to the next MotoGP game MGP 09/10. As I stated before it has gone 10 steps backwards and with arcade style gameplay from over 20yrs ago. I mean if you want an arcade bike game where the bikes don't handle like bikes, but like Jet skis then yeah I guess it will be great.
The best bike game sense EA stopped the SBK series was Tourist Trophy on the PS2. While the game wasn't perfect, it did better then any other recent game. Hopefully there will be a Tourist Trophy 2 that is an actual full game and not just a tech demo. But until that is actually confirmed as happening, I'm betting on Milestones SBK X for a more realistic bike experience. Their recent games haven't been perfect but at least they are trying and moving forward instead of backwards.