I should just mention that I have never played RTCW online, but I have played W:ET for many years (12+) and I'd love to see either of these games come back, be updated with bugfixes and new cross-platform anti-cheat and so on.

So far there is etlegacy that seems to be aimed at keeping W:ET alive, and it looks like they're doing a decent job with the client/server fixes. They also have a mod that comes with it, but I feel their own 'legacy' mod is far from the mark in terms of wolfenstein games making a comeback. What I think people want from a mod is something competitive and really they'd do better by making their mod an etpro clone.

For the game staying alive or coming back, I think what's really needed is a sensible sequal with similar but not identical gameplay, much updated graphics and a leaner, smoother feeling to gameplay. I can imagine some community efforts fixing some of this, but an actual sequal seems far away right now.