Seriously stop sayin BS because you like a feature lol. No Gale as a Barbarian, Shadowheart as a Druid and Lae'Zel as a bard does not make any sense story-wise.
I also thought that multiclassing would have been enough... But it looks like Larian does not care to offer companions a narrative that doesn't make any sense for the sake of gameplay choices. Definitely something I'm not in line with.
That said in a comment : fextralife said that he talked about it with devs and that they were not sure if this would be in the game at release or not.