I'm just wondering if it is possible to downgrade compiz to maverick's version 0.8.6 like in natty? I have an ATI radeon mobile 3200/4330 dual GPU and the new compiz and even natty's compiz doesn't like my laptops card. I understand downgrading will loose unity 3d but I will still have 2d.
In a nutshell: no. At least not without some issues. (I could be wrong).
You probably could purge all compiz packages and then try compile 0.8.6 from source, but I'm not certain it would work seamlessly.
not certain I follow the question, but will try to assist you. Going to restate this as understood to determine if the actual problem is clear. Believe the issue is that when trying to run Unity, your current video card, and ATI Radeon Mobile 3200/4330 dual GPU is not playing well with Unity and therefore producing unsatisfactory visual results, is that correct?
If that is the case, then at the login prompt, you should see a gear by the password window. If you click on the gear, you can select from either Unity or Unity 2d at that time and then login. Subsequent logins should remember the last chosen session and retain your preference from the last session until you choose a different window manager (or choose to install another).
This can also allow you to get to a good known working state to resolve your issue with Unity and Compiz. Would highly recommend running the compiz check script found here:
As it can be valuable in determining if your card is capable with compiz (though it may be a bit dated).