I'm pretty sure this is implemented in a small way, glancing hits, but as I recall, they only come to play at the end of the swing.
The change to the start of the swing I would want; Reduced damage, but the player hit is moved a small path along the swing. This would make it so mauls wouldn't insta-gib at the start of the swing, but rather it hits, deals a bit of damage, and at the middle of the swing the enemy is kind of 'released' at the peak momentum of the swing. I wouldn't mind if the enemy would be ragdolled, but that might be a bit too strong.
This swing-start implementation would reflect momentum of the weapon. At the start there isn't enough momentum to cut, but enough to drag the opponent slightly along the swing. Blunt weapons would have a larger push-back while bladed wouldn't.
We do glancing hits and 'early release' (phases through and cannot damage but can be parried), because we generally prefer more deterministic damage states rather than a smooth curve. The biggest issue with further reducing the viability of early/late attacks is that it effectively cuts down on the ability to get around blocks, and that it would still lead to these moves being used, just to lesser effect (which won't make them any less infuriating on the receiving end)