Visually, eh, there are a lot of things but I mostly just use the roulette unless my company chocobo is already out. Mostly I want them to add variety in mounts as someone else suggested. Faster mounts, perhaps that flee if you get hit as a trade off. Slower mounts that are immune to heavy, mounts that can sprint/ become invincible/ become invisible, gliding and/ or truly flying mounts, etc. I'm sure there are many more interesting things that could be done beyond essentially reskinning the one mount that we have.