While I have no desire to have companions be the sole focus of a patch, I would love to see them get some attention. They've pretty much languished since launch
Lots more customizations.
Emotes like the companion dance. (and loop the companion dance like other dance emotes loop!)
New comments - some that are specific to affection and married state.
More cut-scenes, even if they are just repeatable fluff and don't have an arc.
More letters. (that really, really shouldn't be hard or time consuming to do!)
Up-grade class companions to be on par with HK and Treek.
Idle animations on the ships. (and remove the torso twist when you have them summoned.)