we have no idea what their different class skills are yet
Well that's true. And the specializations aren't very strong in 5e to begin with.
E.g. Enchanters have to go all the way up to 10th level before they get an ability that actually has anything to do with their Enchantment spells. You could easily be an "Enchanter" and cast nothing but Fireballs. Not the best subclass design if you ask me. The relevant ability of any Wizard subclass should encourage them to cast spells from that particular school over others, starting at level 2. I hope Larian have taken that into consideration when implementing the subclasses for BG3.
