I would also like an evil Goblin companion (even with a romance scene). I made a joke post here on Reddit about Sazza:
https://www.reddit.com/r/BaldursGate3/comments/mg6abu/poll_let_sazza_be_so_thankful_you_rescued_her/It didn't go over well but I was just saying there are several instances where an appropriate "romance" could happen. I mean you can already "romance" Minthara and there's that Bugbear/Ogre cutscene in the barn and all of the rest of the lewd Goblin comments.
I can imagine a scenario where the Goblins *don't* go hostile and allow you to stay allied with them, even after Minthara's death. Maybe they don't trust you and decide to send a Goblin with you on your adventures. I would pick a Goblin Rogue with the Assassin subclass, who later may try to actually assassinate you if you go against the Goblins or don't convince it to stay sided with you.
I would also like to see more of the sexual side of the Drow in the Underdark at some point. Their society has always been interesting to me.
Drow Handbook. Love is on p. 28.