There's a simple reason why tank supports are currently the best
tank supports are either doing more damage or equal damage to other types of supports while being tankier and having more CC.
Just look at braum and tahm kench, both have %damage (which btw is broken as shit) which just gives them huge amounts of damage no matter how behind or what their build is.
Solution: let's stop with the % hp damage, it's not healthy in any shape or form.