I don't think MotorStorm will get splitscreen even if we ask for it very loudly.
The next MotorStorm will probably get it, as the developers will get better at developing on the PS3, as you said.
But what I'm saying is that the PS3 games are being held back because there's a low attach rate right now (I wonder why), the PS3 is harder to develop for, and the developers want to sell more games.
When is the next big news for the PS3 going to show up?
During the European PS3 launch.
People all around the world who want PS3s or have them will hear more about it and more about the games, so they will buy more games.
It's a good plan to earn more money or lose less money if your game doesn't sell much. It does have the adverse effect of making people less interested in the console(s) you are making games for.
I'm guessing that in March, PS3s will be very scarce, as there will be a lot more news about it around that time frame.