Please NO flying mounts....ever. They destroy everything MMO's are supposed to be about. Player interaction.
Also...please keep mounts out of the Cash Shop. They aren't cosmetic. They affect game play. Mounts in a cash shop = P2W.
This is an interesting thesis. Why mounts in the cash shop break the game, when they are actually only cosmetic, not giving you any kind of advantage?
How a player with a cash shop mount, be stronger than you with a mount from drop?