"It's optional" is not a good take on this problem at all imo. Commitment to a choice is an important aspect of a well-designed rpg, always has been and always will be.
Respectfully dissagree ...
First of all, there is no choice here ... You dont choose for Lae'zel to be Fighter, for Astarion to be Rogue, or for Karlach to be Barbarian. Those choices were made for you ... and to be completely honest, i picked theese specificly, bcs those choices seems to be a little random. As stated in other topic, Astarion should have ben a Bard. But i presume choices here were made more by wich classes were prepared for EA launch, rather than some strong narative ... In alternative universe we would be arguing that it makes perfect sense for Astarion to be a Barbarian, since Vampires are tougher than humans and his hunger makes him rage out ... just bcs Larian there decided to do different set of classes first.
Anyway, the point is that if you feel like Commitment to a choice is important for you ... there is nothing in this world and beyond, that would stop you to just respect their classes. You reset it ... they get to level 1 blank slate ... first thing you pick is their class. You have what you wanted ... dont you?
I still dont understand why cant we change Race for our hirelings. Lets us play Githyanki as racist as they trully are!