only thing that annoys me about 30 fps compared to 60 is hit detection. i literally could not care less about graphics whatsoever, never have and never will.
I'm sure the hit-detection is quite noticeable, especially in PVP.
I play these games by myself in an offline environment and since PVE is far more predictable than PVP, 30 FPS Vs. 60 FPS doesn't bother me as much. As long as the game is playable, I couldn't care less.