Sprinting is simply unnecessary. I found that when I was personally playing the game I would be permanently holding sprint. It is much better to just be always moving at a faster speed and simplify things.
Wall kicking was just plain broken. I had fiddled with it for several versions before removing it. The problem with wall kicking is that the player could face a wall, hold forward, and spam jump to scale the wall. There is no way to solved this as it is just how air strafing works. I ended up with a stopgap solution where air control would be reduced directly after a wall kick and then regenerate over the next second or so. This worked-ish and is how wall kicking ended up getting shipped but it was a weird hack and felt odd in practice all while only lessening the issue and not solving it outright. In the end either the wall kicking or air strafing had to go and of course I choose air strafing by a mile.
The movement system continues to be tweaked. The same release which killed sprinting and wall kicking added crouching which allows for crouch jumps to scale a single wall height as well as sliding (which is important as you have higher accuracy when crouched). I have a bunch more ideas to work on and 0.2 already has a bunch more improvements to the core movement.