-Many people don't understand the difference between refresh rates and frames per second.
-Many people don't bother to
a) increase their monitor's refresh rate above 60Hz
b) increase the maximum refresh rate setting for the game (cl_maxfps, etc.)
If you are like most gamers and haven't played Quakeworld/QuakeII/QuakeIII with the lights out for extended periods, with rendering speeds (fps) never dropping below the monitor's refresh rate of 85Hz, you won't understand why capping the render engine at 60fps is a bad thing. There is a buttery-smooth, uber magical visual that one can only obtain by ensuring that render speeds never drop below a high monitor refresh rate.
For the minority of us who can and do appreciate this, it is a sad day to hear we won't be able to do the same running DoomIII on future hardware because of a limitation imposed in the rendering engine.
I can understand why network servers would need to cap refresh rates for bandwidth conservation, but why not make it a default option and leave the choice up to the single player gamers or net server admins to decide maxfps?
I'm shocked to see id make such a shortsighted decision. I guess they expect us all to have the slower-redraw LCD flatpanels by 2004 making much of this discussion moot, and unfortunately most of us will never know what we are missing.