Honestly in mass PK (real mass PK) with the insane-amounts of GFX being shot around from the new classes, this seems to have barely (if any) improvement.
Outside of mass PK, perhaps there is a slight boost for people playing on lower-end computers, but in the middle of mass I'm still rocking a solid 5-10 FPS max, which is the same that I had before. The new classes have made it harder to tell if this is actually working or not.
