I've sat on this idea for a while, and figured I may as well speak on it now that the expansion has been announced.
Would it be a lot of trouble to update gliders to function like Griffons through a new mastery?
It's a matter of preference to me; I much prefer the glider skins to any griffon. If flying mounts can retroactively use glider elements, why not the reverse?
It also seems pretty harmless: after you unlock griffon, you have the option of training into griffon-inspired "advanced glider proficiency" or something, and can thus opt to keep using those sweet glider skins.
Thoughts?