Hyao has noted that he would eventually like to have sprites for everyone, they're just coming over time.
If you are submissive / a bottom, you can have a more positive relationship with Gunnar (although from what I've heard, that doesn't mean he's more affectionate per se!).
I will note, however, that you do have the opportunity to have some not-horribly-negative scenes with Gunnar provided you don't get a black heart with him - dual frotting with him, helping him with his shoulder injury as an herbalist.
It obviously will be a slow process, but there's definite room to at /least/ be friends for a mutually-a-top player, haha. I will personally consider it a victory if I can say 'hey' to him and have him nod at me and then go about his work grumbling.