Its very very simple. The issue alot of players, myself included, feel burnt out in order to play at our best and push content we have to do Mythic +, Rank in PVP and more in order to just push a few mythic bosses. Upping the drop rate on gear in raid is only a bandaid to a bigger problem that alot of gear for some classes just isn't viable in Raid. For example - Monks and Demon Hunters HAVE to PVP in order to get their BIS gear. While my idea is not a complete ideal solution, but it would be enough of a solution in order to allow these classes to not feel COMPLETELY forced into PVP / M+.
Bring back Reforging.
The issue behind Reforging in Cataclysm and Mists of Pandaria was that all it was really used for was reforging to your Hit and Expertise cap. When those stats went away reforging had a chance to shine in letting people figure out their best stat weights annnnnnnd it was gone when Hit and Expertise went away.
Reforging would allow us to take some of those less than ideal raid pieces and change half of one stat into another stat. This would make some drops not feel horrible when you get it and can't trade it away.
In the case of the Former Reforging mount - Keep the Transmog vendor on the yak. Maybe introduce a new Reforge mount in the game and have it as another gold sink.