Vlad Rework Idea. Tank killer/Drain tank

Firstly, I think that Vladimir is a champion that should be reworked because not only is he not fun to play(In my opinion as someone with several hundred Vlad games), but is one of the most obnoxious characters to play against. In his current state hes seems extremely difficult to balance. My solution would be for just a full on rework. My general thought about his kit is to make him a tank killer/sustain tank that thrives on having low cool downs. The idea was to make his ult a low cool down debuff that does something to the effect of making consecutive damage instances after the mark is applied deal damage based on the targets max hp. The other part of the idea was to make his passive something like a stacking buff that is applied by his abilities which increases his healing vs the target(s) based on their max hp, its an idea inspired by lifestealer from dota 2. If Riot Games did something like this I believe that he will be a good answer to beefy tank comps instead of just something you pick every game because hes safe. Obviously there are issues with my idea but this is just a rough sketch of an attempt to make him not aids to lane against yet still good at something.