As a Mage Supp main I have to confess Spelltheif/Frostfang tribute damage proc should be reduced.

In addition to having the most efficient form of gold generation outside of lane, they also deal as much or more damage over the course of the lane phase than Keystone masteries.

Id suggest reducing Tribute damage to 5 down from 10, and to 10 down from 15.

Id describe Frostqueen's and it's component items a full tier above the other Support income items which is significant for that role.

It's just getting a bit ridiculous down bot this could tone it down a sliver and give non-mage supports some breathing room.