The lean mechanics is a good thing, but most games out there that use this kind of feature uses Q, and E on the keyboard to activate it and some people are not too comfortable with this keys.
I think it would be very cool if the game allow us to create more flexible "a bit contextual" key combinations, for example:
The shift key is use to run, so if you press shift without the forward key "W", nothing happens then if you press shift when you are stopped plus "A" or "D"(the first key lean you in that direction), the character could lean left or right, actually toggle lean while you keep shift key pressed to allow you to move around while leaning. This kind of combination allow players to not remove finger from main keys and it seems very comfortable, natural and fast to use.
I think there has to be some conditions to run after lean in this way. If you press "W" after lean the character shouldn't run because you are keeping shift + (A or D) pressed, so if you press W the character should move slowly forward and only if you release A or D the game should respond to shift + W as a run command.
No game out there that I have played uses this kind of key combination to lean and many players have tried to create many keys combinations to make this movement more natural, so the possibility to create this kind of flexible shortcuts, though a simple thing, adds something good to the game.
Just to remember, I'm not suggesting to eliminate the use of Q and E keys to lean, but just adding more ways to create shortcuts to actions.