Sounds like a decent anti-kiting thing, unless it lets melee hit so hard during disengange that it essentially makes disengaging impossible. I don't like infinite kiting, but on the other hand I feel there are too many RPGs that favor melee. Ranged is often very weak (for example NWN1 + 2 where archers are borderline useless).

Balancing archers vs melee is fairly difficult. Let's hope they get this engagement system right, so it doesn't favor one over the other (too much).