Can you explain this a bit more?
For me I like to "crouch spam" as it's called, to make it harder for the enemy to kill me. It feels as if H2 Classic or Anniversary doesn't have the same crouch behavior that Reach and CEA does. I can't crouch at full speed. I have to slow myself down. And this occurs on both Mouse & Keyboard, and Controller.
You can crouch properly (if that's what you're referring to) with a controller (in this one you automatically slow down due to the way yoy have to move the sticks). I've done it plenty of times on Xbox to outgun someone. The difference is now you can do it with MKB as well (which didn't have any way to change your speed). Did you update the flight to the last build?
During the beta, I could tell crouch while strafing worked fine, but never got a teammate to test crouch jumping in custom games.
However,
you might be referring to the H2 Anniversary portion of multiplayer, which paired with a lot of changes to the original, doesn't allow you to crouch faster than at a fixed rate.