Actually, GG already stated in the past - while developing KZ2 - that the main hurdle was not as much with the rendering, as they have shown already with the 3d option, but with the datastream.
IE the trouble was in having to load a lot of different level data for the two players depending on their position. Yep, apparently KZ2's level data was enormous.
As far as I know KZ3 has improved datastream subsystems, reducing the loading hiccups to nothing, and a little more graphic memory freed by offloading the antialiasing to the SPEs using the MLAA developed in GoWIII. Thus, we can't be certain, but we can hope.







