While it might not be the most glaring issue in the game right now, I believe that the Restrain effect is an important topic that warrants a discussion.
It has been a vicious cycle brought by the focus in burst kits; heroes had to be tanky or slippery to survive burst, which as a result brought heroes that required more burst as to not allow heroes to go away with one of the multiple escape mechanism available in the game. Not sure if completely true, but from my experience, the Restrain effect got introduced as a more balanced way to counter the increasing escape mechanism that plagued H