the option to do this in no way shape or form affects your choice not to do this. If only want to play Wizards you should not be offended that there are options to play other classes. You can still choose just play only Wizards in your play-throughs.
"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. The very fact that we can change our class at any later point cheapens the initial choice of class. This goes doubly for companion characters whose classes are tied to their stories and express things about them.
