Did you ever get that ugly flow problem resolved?
I'm having the same issue with another Pfister tub spout, the Contrempra model.
There's nothing wrong with the flow, it's plenty strong. I tried removing the diverter as a test, and it actually did improve the look of the flow a little bit. But I like to be able to take a shower, so I put it back in. It seems the diverter, by design still covers half of the spout hole when it's open.
I'm wondering if this is a design flaw or is there a problem with my particular spout. I'm thinking of trying to streamline it a little on the inside with some epoxy putty, and try to make it a little more hydrodynamic. That would be me grasping at straws though.