In the config settings, we can bind a key to (when held) make us "walk", so to speak.
Now, could we have the option to set this walk speed as default, and bind a key to make us "run" instead? Having a "hold/toggle" option would be fantastic as well toggle walk? I think there would need to be some minor adjustments to player speed in custom game mode options to make this more effective, but this isn't much of a problem.
The reason I bring this up is mainly because I'm fed up with how sprinting mechanics behave in arena shooters these days (sacrificing shooting guns for faster movement)... the biggest offender (I believe) is Halo. I can see this being an excellent feature, allowing us to switch between slow and fast movement on shooters with arena gameplay (Doom, Halo etc.) especially when using keyboard-type peripherals.