But if he's already set to leave and Gale's not that's pretty interesting.
Well, as of Patch 3 when you speak to Gale at the party he does threaten to leave if you sided with Minthara. You need to persuade or intimidate him into staying if I remember correctly.
I didn't have that. But I did feed him a lot of magic items...
I had it in two separate runs. One with Gale at neutral approval (I'd been starving him) and the other at high. Does he close an eye on the slaughter of a whole village if his approval is exceptional? Now that would be interesting...