You missed out on a lot (through no fault of your own, mind), he's objectively one of the better romance options. He's such a sweetheart when you get him to drop his egomaniacal archmage affectations.

He gets a lot better. He drops the big magic man persona and reveals a very scared and vulnerable core.

I didn't have Gale in my group of 4 so only got the basics of his story but he gets more friendly as the game goes on, never finished the game (should get on that) but I see a lot of fan art of him.. also I like his purple sweater I think it's the only camp outfit I didn't tinker with