We have had hundreds of various mounts since vanilla World of Warcraft began. There are now four categories of mount types: ground only, flying (the traditional static speed introduce in The Burning Crusade, which can also be used in ground only zones as a ground mount), swimming mounts for under water travel, and the latest is the dynamic 'Dragon Riding" mounts for more than double the static flying speed.
I would like to point out in this observation/discussion (not a poll or opinion board here) that while “mount diversity” is incredible, they all share one common thing, you have to “mount” them. I personally really like the Tazavesh Gearglider, and its counterpart the Cartel Master’s Gearglider. Small, lets your character stand unlike the Archmage’s Disc from Legion, or the cloud discs from MoP. But one mount that has eluded the developers is the character themselves. ONLY druids it seems, can shape shift into a bird and fly (and can Druids dynamic fly?).
I have seen posts over the years (since I began in 2009 anyhow) that indicated players would like a “cloak of flying” or a “ring of flight” or such. In playing recently the last few months the Firelands Raid to try and earn the elusive Pureblood Fire Hawk mount, I have been hitting Alysrazor and using the “Wings of Flame” buff to fly over the moat to get to the palace of Ragnaros I see that it is very possible to have our own flying ability (even though it appears that you are swimming in mid air 
).
I would definitely like to see a mount that has such an appearance. One graphic could be that the Harmonious Wings of The Ascended
It would be great to have different color versions (fiery orange does not work with every character’s role-playing gear), in particular, something white-blue when used to fly and another version that has violet and gold. If using a ‘person’ mount in a ground only mount area, then perhaps your character just levitates like the priest class can but with your ‘wings’ fluttering about behind you as the Harmonious Wings do when you are mounted and riding/flying about.
I’m sure that many players who have been frustrated at trying to gather nodes (ores and herbs) with the new ‘2D graphic area hogs - aka dragon riding mounts that are drakes, and wyrms’ would consider a smaller form-factor when doing their gathering. That has been a problem for many when nodes are piled high with other players (and bots) trying to mine ore or gather herbs and you cannot click on the node because you click on numerous players on their mounts. While gathering seems a good idea without having to dismount, it really is not because of the graphic mis-mash on the screen.
I would be willing to buy such a ‘mount’ from the Blizzard Shop just like the I have for transmog gear, pets and specialty mounts in the past, such as the Celestial Steed and Heart of The Aspects.
This is just an idea, but great things start in small spaces that grow with interest and gain with cooperation and collaboration. Hope that something comes of this. Thank you for your time.