I have two strongholds, and being in them is like being in another spaceship. The following would be nice to see:
1. Ability to add color to walls and floors with dye packs or even different wall texture materials (granite/stone/paneling/stucco/prints etc.).
2. Ability to craft/purchase furniture that looks comfortable.
3. Ambient noise options (music, chatting, in cantina classes clinking) outside spaces soft traffic noises. (Coruscant could include soft construction noises outside)
4. Decor themes.