It's my worry, that in the end pretty much everyone will be built this way in a min-max-built ^^
Realistically speaking, why would it matter? We're not playing an MMORPG or an eSports title. Let's take it back hard to some basic DnD. There are some pretty insane min/max builds out there for DnD but most players will do what they went even if not directly through RP (I want to be a "death knight" even if they don't literally RP as one) and a good GM will capitalized on that.
The default campaign here is basically the same thing with Larian as the "GM". It's your choice what difficulty to play on, it's your choice what to build your team (or your group's, I guess).
So your worry is kind of silly. It's also horribly wrong, anyway, as casual players rarely ever min max and even I rather enjoy the challenge of off builds so me and my crew definitely won't be.