One thing? Tricksy that. I'd have to roll a dice against a few.
The ability to open more than 2 windows (inventory, character, etc). Able to move windows around. Crew skills not interrupting what you're doing (using the market/cargo hold) Modifiable UI - move hotbars around, shrink them, extend them, etc. Solo/group/raid versions of instances, so one isn't locked out of content for a playstyle choice - obviously loot tables are modified. Items on the market being able to be put up there for longer than 2 days. Options for characters making it a viable choice to stay hovering around the middle of the light/dark spectrum, else there's no choice, everyone pretty much has to choose the extremes in conversations. Especially irksome for the dark faction, where they aren't evil so much as competing to be the biggest arsehole. Recognising that a guild is an OOC construct for players, and not an IC creation. Allow whispers across factions, it's the players talking, not the characters. PvP abusers would use TS/Vent to circumvemt it anyway, as it is that circumnavigation is foist upon everyone to stay in contact with friends. Allow "friend"ing across factions, it's the player's friendships, not the characters. As it is a person playing their light character couldn't know if a dozen friends are playing on dark characters. When adding content to Hoth, remember the Tauntaun when adding travel options. Add light/dark to the crew skills that need them. A biochemist gets to be light4 much faster than a synthweaver because of that absence. Whoever made some of the more arduous jumping to the datacron routes, kick them in the balls.