Recently, we've seen Ezreal begin to abuse Seraph's/Muramana because of the dual scaling on most of Ezreal's Kit, but primarily the Q. It's short cooldown, ability to apply single target spell effects, low cost, and dual scaling, means that Ezreal is the only "Hybrid" champion that can get away with this.
However, this is a very "Niche" build, like Blue Ezreal. Very few champions can build it, if any, and it's all because of Ezreal's Q.
So, a proposed change to Ezreal's Q to avoid nerfing Seraph's (AGAIN), or Muramana, I propose the following:
Ezreal's Q is now "Adaptive". With the tech for Adaptive scaling now in the game, it would be worth testing making Ezreal's Q adaptive. If Ezreal's primary stat is AD, his Q will adapt and be the AD scaling, on hit effect spell we expect. If AP, Ezreal's Q shifts to Magic Damage, with AP scaling, and the ability to trigger spell effects. (Unsure whether to allow onhits or not, since Lich Bane is still pretty core to AP ezreal).
Basically this solves a few issues. It means a primarily AD ezreal can't double dip into Seraph's/Muramana to get obscene damage from the Q, while also making sure the Tear items don't get nerfed for other primary users that want to build them.
If that can't be done, then simply making it so you can only buy one tear item would be sufficient, easy to implement and low impact. Changing Ezreal's Q would be better overall to the health of the champion.