One of the things that killed Visage as a support was a massive increase in Soul Assumption mana cost. At one point it was increased to 200 mana and fluctuated between 150 and 200 ever since. Now, at a much more reasonable 125, Visage can now use it three times before running out of mana and given how it is a potential ~250 damage nuke at level one, this change should not be underestimated.