I think that implementing leaning in AoS is a good idea.Why?Becauze that way cover would be more useful.You would only stick your head and gun out.This would be a advantage for the guy in cover.Pressing q would lean you left and pressing e would lean you right.
Advantages:Since you only stick your head and gun out it would be hard to see you so you can get an easy kill.
Disandvantage:Since you would need to stop for a sec to lean you would be a sitting duck.And you wouldnt be able move while leaning.
Im sorry if my grammar is not good.