1 - Has defensive values 2x better than the light set and loses only 10% of damage.
2 - Has the same movement speed
3 - Dash costs less stamina
4 - Very easy to find good equipment since rare exceptions still use light set.
5 - Defensive values like aversion and resilience scale sooooo much better.
AGS why do you hate the light set so much? the game is full of average players full of defense, you need to value the elaborate gameplay.