I agree with people who just want walk for positioning. If you think about FPS on a controller like Halo, they have analog walk/running, which is actually superior to kb/mouse. I would prefer kb/mouse to be superior in every regard (it is everywhere else obviously).
We can mitigate this with digital inputs by at least having a walk modifier. Crouch modifier should be even slower than walk so that almost gives a range of options close to analog movement input.
As for crouch, it's a standard in almost every FPS so it being missing feels like I'm going back to the wolfenstein days, it's unsettling. I think there's nothing wrong with Q3 crouching for the most part. The smaller hitbox can be offset with slower speed. If you crouch in midair you lose most of your ability to gain air speed. Crouching can also help with precision movement in the air if it slows you down as mentioned before.