I think that supports need to have an actual role. Because it seems that most supports can just go mid and tear. Why is that? They can outperform fully fledged mages in a 1v1 lane? Why are they labelled support, if that's the case? Especially if they're probably better there. If they have heals and hard CC (Looking at you, Nami) with low mana costs, I think you seriously need to consider curbing their damage.
Just a thought.