I'm not for changing the gameplay, just fleshing it out some!
1. More interactive environment, like being able to sit in chairs.
2. Less pathing on outdoor worlds.
3. Collections from mob drops to complete unique items, etc.
4. Mini games like Dejarik, Sabacc. etc.
5. More fun side quests in all zones, like answering trivia, lore riddles, etc. Not all quests need voice over by the way and a cinematic!
6. Player instanced housing in various places, would be great for immersion.
7. Named force crystals for end game.
8. Reasons to go back to lower planets like Tython or Korriban at higher levels. NOT Taris, lol!
9. The mouse over mob tool tip to show how many killed out of how many needed, ex: 4/5 Black Sun Thugs.
10. Enter your ship without launching into space! Maybe I want to sit in the hangar.
11. As you add worlds, make them larger and more dynamic with lots more non linear quests, like dailies.
Thanks for your time!