Fixing the Support-Mage Problem

In the past (and now), any time a support is given good scaling, they become better as a mage. In response, Riot lowers their scaling but buffs their base ability numbers. This turns them into abusive supports which in turn nerfs come in to turn them into just alright supports.

The dream of support itemization will never work. Giving more scaling on supports makes them a better support Mage, not a better support. I've got an idea to fix this, although it may be a bit brittle. Here goes:

Increase scaling but put a cap on scaling

This means supports can scale up very well but because of the cap, if they are played mid lane, they will quickly become useless after 1 big AP item like rabadon's death cap (same thing with tank stats like on Leona/Taric). Good solution or too brittle?

tl;dr cap support scaling so that they can scale fast with less AP but don't just become mid lane mages because of the potentially higher scaling with more stats