I personally think you should be able to change starting class. However, I do think there should be a pop-up warning, such as:
“This character’s story and dialog options were created under the assumption that __________’s starting class would not be changed. Special dialog written for this character may no longer be consistent with his/her new class. Changing the character’s class may negatively impact the player’s experience.”
This is a decent compromise.
Remember the human (This is a forum for a video game):
