. We have already notified your loyal friends and mortal enemies of your unexpected transformation and in the spirit of politeness requested that they refrain from commenting on you suddenly swinging swords instead of spells. Oh and don't worry, we won't tell a word to Shar - you'll still be her favourite errand girl!"
I think you're looking at it from a different angle than it's intended. Instead of considering it a change of class, consider it more like retconning the class. We're changing who they've always been. Sure, it's immersion breaking, but it's also immersion breaking when I get up to refill my glass.
The option being offered is "hey, so you think Shadowheart is more interesting as monk or druid? Knock yourself out!" It's just a different way to tell the story
