There's a difference between an "Exploit" and the titles aforementioned "Balance problems"
It's not a balance problem that you can quasi-long rest by respeccing. Given how easy it is to simply just long rest, with times you're not able to long rest (Such as in the Mindflayer Colony) you can't access Withers to respec either.
It's not a balance problem that you can steal potentially infinite money from vendors because just normally playing the game can give you far more gold than is required to purchase every single item in the game.
It's not a balance problem that Withers will revive characters for 200g because you get so many resurrection scrolls that he's not actually needed. Not to mention the plethora of vendors that sell scrolls for about the same price (Which even if you're not respeccing to force restocks will provide ample amounts of them) and again... Normal gameplay will net you literally tens of thousands of spare gold.
Literally none of these "Problems" actually provide any benefit to someone to who goes out of their way to use them over the normal game systems. Maybe they're unintended and can be considered "Exploits" but they're hardly balance problems.
Maybe if gold was actually a limiting factor outside the first 5 minutes of the game, maybe... But then you can just have a Hireling Bard play some songs to generate infinite gold so it becomes a non-issue anyway...
