1. Anyone who actually plays like that is in dire need of a mental health intervention, and I don't think there's any need to balance the game around crazy people.
2. Performing this procedure of madness would have a miniscule effect on the difficulty of the game.
Minuscule effect on the difficulty?
What are you like 15 years old? None of the all time great RPGs from the past like Fallout 1-2, BG1-2, Wasteland, etc allowed to competely respec any character at will , any day any time any place for no price .
Respecing is not a part of the d&d gameplay in general, it’s also RP immersion breaking being allowed to change key characters classes at will just because
Like shadowhearth becoming Light domain or totally different class yet acting all game as a trickery/ shadow cleric .
Withers is OP and it’s ok for him to exist in Normal mode for casual people who likes to change their build all the time, but having him on Tactician which is supposed to be for experienced hardcore players is a travesty.
Tactician should be all about making difficult choises and planning ahead - like choosing to start with 8 Dexterity and gimp yourself most of act 1 but with the idea to get the gloves and up to 18 this getting huge stat buff at the Crèche- this should be a tactical decision, but with Withers you just respec the moment you get them for free and that’s it.