Alright, sure, here's some ideas lemme just throw at the wall
Character/Customization stuff:
-*Complete revamp of the character customization screen*, especially in ways that would make it easier to manage sorting through the massive amounts of mod markings/items. The scrolling right now is incredibly finicky even on lists that arent super huge. You could improve the scrolling (maybe so it's more smooth and doesnt just skip to the next item), or make them into mini pages that you click through. Perhaps even add previews. You could even have the camera focus on whichever area you're customizing.
-Multiple layers of markings.
-Being able to more easily copy a color to another part.
-Horns/antlers/saber teeth/body spikes and spines that are actual colorable parts.
-Colorable items.
-Every part of the eye is colorable, pupil, iris, sclera.
-More and better mane/tail/ear/wing options. And more variety, like long manes, curly manes, manes with flowers and items in them, ponytails, etc. Fish tails, rabbit ears. Different styles of bird wings and insect wings and more fantasy looking wings.
-Updated character models, part models, textures, and animations. (especially the wings).
-Domestic cats and dragons
-Different "stances" and walks to give more personalty to your character, like a lowered head and drooping tail for a downtrodden character.
Gameplay:
-Questlines and a battle system for both PVE and PVP and things like skill trees, similar to a traditional mmo.
-Personalized character stats and skills, for uses outside of battle? Like one stat lets you move quicker.
-Hunting for food, perhaps you dont need it to live but it'll give a bonus? Could have things like stalking your prey, or anything more engaging than like the IT "hunting" system.
-Making dens/personal homes that you can invite your friends to, or other people can just visit if its not private.
-Collecting items for decorating your home. Maybe they can be collected from harvesting natural materials from trees/bushes/rocks/etc. Perhaps they can be crafted into even more advanced looking stuff? Or u can just lay down a bunch of flowers you collected in ur house. Perhaps there are rare items that take more dedication to obtain.
Misc:
-Shaders! Dynamic lighting! Perhaps you can turn it on/off.
-Being able to open a big map where you can save waypoints for places you like.