Diablo 4’s primary problem is balancing.
This situation where a build performs 10x,20x,30x better than the others should cease to exist immediately.
If this is a question of philosophy, it is a bad philosophy.
If it’s a matter of difficulty, you’re being lazy.
Firstly, make an arena/wave system similar to Last Epoch, it’s a perfect structure to test class limits.
How will the balance be?
Make a barbarian HOTA build with maximum gear and see how well it performs.
Does it reach wave 700? Great, we have a parameter.
Now you’re going to make double swing build and make it reach a result similar to 700…
can it reach 500? you will buff it until you reach a result similar to 700.
Now you’re going to make a whirlwind build, whirlwind build hit wave 400? you will buff until whirlwind build reach a result similar to 700.
Ended with barbarian? go to Druid, redo this process.
After the classes are balanced, you produce real content.
If you want, I’ll do it for free for the prosperity sake of Diablo 4.
This is what balance means, balance is about proximity.
No matter what system you make, if you don’t balance classes properly, the game won’t be in a state of prosperity.