[{quoted}](name=Hexs Fortune,realm=NA,application-id=3ErqAdtq,discussion-id=g4Oe8XWc,comment-id=,timestamp=2017-06-05T21:06:01.611+0000)
That is designed from the ground up to fulfill the fantasy of powerful ranged damage from the support role. CC can even take a back seat for this one.
Give the champ incentives to want to be in a duo lane to keep them out of mid
People don't force mages into the support role. That's like saying "if the pieces don't fit, we make them fit."
People take mages support to find out if they work. (or because they already know it works) Riot simply takes the lazefaire approach and balance around the most OP and popular option. (And people just complain about either A) WTF The support does too much damage or B) Stop ruining my main)
But to answer your question, most mage supports don't put CC on the back seat. Champs like Morg and Lux work in the support role is because their CC allows them to serve the role as catchers, similar to thresh or Blitz. (And Zyra was recently defined as a catcher as well) With the main differences being that your have damage scaling. That can be built up if your ahead. But with that CC, your never behind because you can always serve as said catcher. You could even forgo damage in favor of utility items, and still have that CC to be a useful support.
But put that aside, what can you do to a mage to favor the duo lane? I can think of 2 things, either a) give them synergy with your lane partner. or b) give them synergy with multiple targets. The former case I'm not so sure about, since Ally synergy is usually a utility concept. The later case would make damage execelent in the duo lane, that would translate to a lot of team fight power. (Would also make them hated in ARAM) Though in that case, I think Brand already fits that bill pretty well.