1. Customizable keyboard keys. (Can I use the freaking arrows to move the camera please?)
2. Mounts. (Not just chocobos, find a reason to get us to ride a wall climbing lizard, or a gliding beast to platform through areas that chocobos can't get through)
3. A better UI, that includes an easier to use chat box.
4. Class-Specific Armor Sets, that you get through elaborated quests.
5. Better quests, with CSs and fun fights.
6. More weapon types, like great swords, whips, crossbows and so on.
7. Mail system!
8. Unique NMs that require a strategy to beat. (think Charybdis, Kirin, Fafnir and so on)
9. New cities/areas with gear unique to those areas.
10. Better animations that includes emotes (If you look closely there are alot of poses that are almost identical through races, most prominent is /sit) maybe add ones that take more than one person. /handshake, battle actions (GLAs will understand) and better leveling up fanfare. (Check out TERA online's level up animation...)

I kinda cheated a little.