It’s much easier to balance the game around 3 pure class predetermined companions than around the idea of 3 fully customized optimized build multiclassed ones .
In short Withers is 100% a gameplay feature not a Qol feature
If any fight can be won with a solo super build why does it matter what can be done with companions?
I agree with your point that Withers is a large advantage to the player, but I also can see how having the ability to re spec allows a player to experiment and learn the game more quickly. This, in fact, makes Withers a QOL feature. I mean if I had to play a new game to experience every build combination it would be pretty stifling to my game QOL.
It would be nice if Withers was a setting.
Withers is just not needed to win any battles. It's not an advantage to respec your character in the game because you simply don't need to respec your character to win. As such, it's more a waste of time than anything else. I do see how it's useful for folks who want to experiment, and especially for streamers who want to make videos of various class combinations. But to actually get an advantage in combat? Shrug. Once you get a 100 on a test, you can't beat the test any more hard.
Beating Minthara was mentioned above. This is not hyperbole, nor is it bragging: give me a character class. I will start as that class and initiate combat immediately in the goblin camp, starting with the guard area... then, without stopping, I will continue into the courtyard area, still fighting, then I will go through the doors, still fighting, and I will fight my way to Minthara and beat her. All without stopping. Along the way, i will take out Gut and Dror, as well as any other gobliin that gets in the way. I have done this more than once.
I used to do this sort of thing all the time back in EA when the level was capped at 4.
The balance needs a serious overhaul. Getting rid of Withers isn't going to cut it.
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We need better AI. much better AI. We need more enemies. We need fewer potions and elixirs. Camp supplies need to be seriously rationed. We need Honour Mode. We need no rest areas. Haste should be entirely removed from the highest difficulty level.
What we don't need are inflated stats and hit points on the enemies.