User blog comment:TNickxx/Y U NO AD Support/@comment-7463332-20161211051827/@comment-1330314-20161211232503

I think that, if you're designing an AD support, that champion will, by its very nature, contribute DPS to their team. If that's not what you want, then you'd be better off designing a tank or AP support. Like you said, mage supports are picked for their damage on top of the CC/utility they have, and the same should apply to AD supports.

I think one way of preventing AD supports from just becoming carries with too much utility is to tweak their scaling: already skirts the boundary between a marksman and an AD support simply because she doesn't scale amazingly well with AD, and having a champion with even less scaling, but more utility, could make for a proper support. Melee AD supports could likely get less severe scaling restrictions, since as you mentioned as well they need to build tanky.

I think part of the issue right now, though, is that AD itemization still goes too much into damage on its own, what with crit and attack speed acting as major multipliers: this might be the topic for another discussion, but I think crit needs to fundamentally change, and marksmen shouldn't be made late-game champions by default. If a champion is to be strong late-game, that should reflect itself in their own kit, and not their itemization. As long as marksman itemization remains so focused on raw stats and pure damage, AD supports will always be somewhat difficult to implement, so it might be worth adjusting items as well.