All of these things.
I would love to be able to walk up to my characters' LIs and just give them affection - hugs, kisses, 'hey, baby, let's go back to the bedroom for a bit', etc.
I would love for them to turn up in the character's quarters when they want love and affection.
I would like more letters - once a month, every couple of weeks, whatever.
I would like to know that Corso really meant it when he told my smuggler that he would love her and stand by her even if that meant that there were other men in her life, because, let's face it, there totally will be other men in her life.
I would like to see the opportunity to ask your LIs to marry you if you have previously turned them down in a non-relationship-ending sort of way (in an I-am-not-ready-for-this-kind-of-thing sort of way).