These are not in the order of importance, just in what order they came into my mind:
1. Stop destroying things people have spent time on. A lot of time had been spent to get centurion gear, now not even worth what you get from vendors. Lot of people spent time to get battlemaster title only to see everyone get war hero after Ilum failures. PvP commendations is exactly same story. Maybe it is just me, but this sort of things make me lose interest very quickly.
2. I listen to the podcast and I hear them giggling while implementing totally useless stuff like rocket boots or the whole legacy system. Prioritize "things to do that lead to rewards" in the game over novelty features. To be fair, some good stuff have been done like responsiveness fixes and probably some of the pve content (I dont know about ops, I dont do them). Also legacy might become something cool, but right now you could delete it from the game and it would not have any effect on my playing.
3. SWTOR is a direct competitor for WoW so atleast compare your features against theirs when you implement them. Ilum type "outdoor" pvp has been done in WoW and there has been much of the same problems and solutions. I'm not saying wow is the perfect implementation of everything, but there are lessons to be learned.
4. Accept the declining interest in the game and merge servers or something. My server seems very quiet.
5. Open up an API for addons. People like different things and the basic UI will always be lacking for some players. Addons also offer change when you get bored of the UI so even if the default UI would be great, it is always the same.
6. Make dueling something people can do. Good example is wow, where do you go if you want to duel or watch duels? Outside of orgrimmar (atleast this was the case when I played years ago, dunno if it is anymore). If I am at the fleet, I have no idea where to go duel. Should I go to some arbitrary planet and bring a friend?
7. Remove fleets and replace them with planets. I want to see the other side killing me in my own capital! This would also fix the issue 6 if you could just go outside to duel.
