Mages feel like they don't have their own keystone or rune tree(sorcery is far too generalized)
Unlike Precision which is highly specialized and can only be used effectively by AA using champions(ADC and some bruisers maybe Azir), or Resolve which has a number of runes that will only be taken by tanks for a number of reasons, or Domination which feels like the quintessential assassin tree, Sorcery is just far too generalized of a rune tree.
I see everyone taking sorcery runes on a number of different champions, champions that are supposed to be taking other runes. Comet and Aery have no niche uses or niche champions they should be used on they are just raw and general damage that every champion can use. Phase Rush which should be a niche mage keystone feels terrible on every mage right now and is being kept that way because of all the bruisers that want to use it.