If you think about it light armor users generally keep the distance, have stuns, +20% damage and they can easy roll and run away.
While medium armor users need to be in range, have also stuns, +10 damage, are easy to stun, kite and have it difficult to run away safe. Plus desync problems what makes them hit air %50 of the times.
For that reason give light armor user the small roll and medium the large.
Now if someone goes medium with range build he will just not get the 20% extra damage.
And in some way doing this you are balancing the game.
let me make this simple for you because i dont think u can keep up otherwise :
medium armor can evade 3x, has more armor and can stand cc better than light armor weight.