Melee charge is a nice idea, but it should have some downside/restriction or whatever (at cost of current movement points or high cooldown or something). I think if this isn't the case that there ain't much of a point anymore in equipping light amour, since you can 'sprint' (melee charge) your way though with heavy.
Maby the charge length should be determined by the armor you have equipped, for instance only 2 spaces for heavy but if you are carrying light amour you can melee charge 5 spaces.