There's another Q&A with John Carmack on Thresh's FiringSquad talking with the id Software lead programmer about the changes to the Quake III engine mentioned in his most recent worklog (story). Here's part of the exchange towards the end of the piece that touches on the footsteps issue, and opens the door to the possibility of some sort of pre-set "pro mode" geared towards high-end competitive play:

Firing Squad: Would you consider turning off footsteps only for the tournament mode of gameplay? The weapons idle sounds and item pickups should be enough to keep players on their toes, and a 1 on 1 with footsteps is guaranteed to be much more "dead" and quiet compared to one without. Also, if you think about it, since sound is so important, taking out footsteps can also keep reduce bunnyhopping/strafejumping, since they'll be able to remain silent at full running speed (otherwise the convention goes "why should I run and make footstep sounds when I can go faster by bunnyhopping?") Thanks again, and sorry for the constant badgering!

JC: I have been thinking hard about that. I see your points, and they make sense, but we just added a bunch of character specific footsteps, and for non-professional gamers, we think they add to the experience.

If there were a small set of professional rules that I agree with in theory but have chosen not to pursue because they conflict with more common play, then an official "pro mode" might make sense. Any other suggestions along those lines?