Well you could always play as a sorcerer yourself and leave Gale as a wizard, but it’s really up to you.
He does have lines about studying magic as opposed to it being an inherent ability for him, but sure, that could just be before his condition. It certainly doesn’t seem it would a huge contradiction to me. At worst there might be a few lines that don’t make total sense, but some would say there’s already things in the story that don’t totally make sense.
If you’re happy to headcanon a bit and can just brush over himself or anyone else referring to him as a wizard, I don’t see why not. Similarly with Jaheira, people are going to call her a druid, but could she be a “druid” who just doesn’t use wildshape or cast most druid spells and fights like a ranger? Depends how much inconsistencies like that bother you?
