The main issue I have with stamina on mounts is that mounts do not regen stamina while despawned. This forces people just to leave their mounts out all over the place trying to let them regen stamina. This is not a good mechanic. I understand you don't want people despawning/respawning mounts to instantly regen stamina, but there needs to be some kind of regen while despawned so you can get off your low stam mount, put it away, and have it at full when you are ready to use it again. Either make it slowly regen stamina while despawned or just go to 100% stamina after despawned for 60 seconds.