I actually think that the problem is not the lack of control, but the many possibilities to control things. The hard part is to setup the correct factors correctly to get the wanted simulation.
PhysX is just too prone to problems. Even if you are able to properly set up enough fail safes to support normal actor movement in PhysX, you would be wasting tons of processing power, and the solution would be delicate and full of bugs. Full physics solutions tend to cause objects to bounce and jitter around their environment, which would make things look extremely ugly at best.
Once again, if this solution works well, why doesn't any other game developer use it?
I btw heavily doubt that the ellipsoidal bounding box is responsible for strange results when tracing.
Here's a test case: create a block in wed. Place an entity above the block, such that the entity is partly on top of the block but mostly off. Now use c_trace in combination with USE_BOX to trace straight downwards from the entity. A box or cylinder would give you a surface normal of 1, but since the trace is really using an ellipsoid you will get some crazy number between 1 and 0. That is bad.
So, once again: boxes and cylinders are used in every engine I can think of for a reason. They work 99% of the time, use little processing power compared to highly complicated solutions like PhysX, and are simple to create and maintain (relatively speaking). They are the optimal collision method for all types of games, from first person shooters, to platformers, beat-em-ups, sports games, and adventure games. So why does Gamestudio use ellipsoids, of all things?
