I would like to see updated HD versions of Swift Spectral Tiger and Swift Zulian Tiger (but as seperate mounts), like how it was with updated Qiraji mounts for those who originally got them.
Updated versions of other racial mounts (like Night Elves, I know new mounts were added in Darkshore etc.) but I’m talking about updated versions of racial mounts that have gems on their armor like Night Elf Sabers.
Also this,
A Phoenix mount with a new, unique model that has animation for turning into ashes then reborning from flames for idling or /mountspecial, like this one:
www.youtube.com/watch?v=cOj7u0X4P7g
I don’t mind if this last one would be a Store mount or not, just make it happen please, so I can instant buy it. 
I got SO many more amazing ideas about the WoW (for mounts that is at least), if only if they put me in charge. 