Exploits matter and should be addressed. And Withers is an easy one to address. What’s your problem with removing it in a new mode Gottfried? Since you think you are the better player and the only one not exploiting the game your conclusion is that ‘it doesn’t matter’?
It doesn't matter as it would not change the overall difficulty of the game on tactician for most players. Lets take Withers, would removing him raise the difficulty level of combat? No, because nothing has changed, the NPCs are no tougher, their AI is no more intelligent, and their melee/spell options they have would not have change. The difficulty level of Raphael fight would not change, the encounter will preform the same with or without Withers.
Removing respecs from tactician only impacts players using respecs to complete the game because a) tactician is simply too difficult for them or b) they have chosen to make it difficult for example soloing boss encounters so they can video it. I suspect the majority of players playing tactician don't fall into camps a) or b), I certainly don't and I suspect neither do you. So removing respecs would not increase the challenge for them as it would not fix the fundamental problem, that tactician is not that much more challenging than balanced.
Personal speaking removing respecs will make it more difficult for camps a) and b), but it does nothing for me. I certainly don't have a problem with some players using respecs to make the game easier for themselves, be their reasons a) or b). But some here do seem to have a problem with camp b) soloing boss encounters so they can video it. Removing Withers will certainly make soloing more difficult and that's the real motive for those asking for these fixes, it certainly won't make tactician or a higher difficulty mode more challenging for the majority.