Is this a case of sacrificing the awesome nailbiting lifesteal-tanking of carries in close fights for the sake of balance reasons, or is that very gameplay something considered crappy to be on the other side of?
Lifesteal is a weird statistic. That nailbiting lifesteal-tanking is fun up until the point where the carry can just sit there and autoattack you and gain health while doing no action.
There's this magical line that you cross from 'this is awesome and intense'' to 'I'm just going to stand here and drain-tank off of you because my LS is higher than your sustained damage.'
We're trying to find the right point such that we mostly get the nail-biting moments and not the boring 'Well, Jax/Warwick/Draven are just going to sit on my face and gain health because their sustained vamp is higher than my sustained damage.'