How good/bad is class balance really?

[Kralljin]

Well, the devs back then came from other MMOs, so it is not like there weren't years of MMOs (or RPGs, even with pvp elements like Diablo)

The people in charge mostly had MMO experience from a player PoV, not dev.
And even then, no dev could even boast a 15 year experience on MMO's at the time WoW was in development.

Leaving out whether some of these people who had experience from previous MMO's actually worked on class design / balance.

A 3D Art designer who previously worked on another MMO can most certainly not give you any solid advice on class balance.

As for "but after 15 years, you should get it right much quicker." I'd give you a point if there was any MMO out there that people praise for their fantastic class balance and then I's still take a hard look at that and try to figure out what those devs could that others can't

No, because saying "the community got smarter" is only leaves out the other half, the devs also got smarter, because they get more experience on their job.

If you work for over a decade on a certain project, certain mistakes shouldn't happen anymore (or at the very least, get fixed much quicker), because over the years you should have learned to avoid these things or develop a strategy to detect them earlier on.

The devs 15 years ago most certainly did not have internal tools for simulation, nor the wealth of data access that Blizzard nowadays has.
So yeah, i'm more willing to give them a pass on fucking things up there.

To me it was more about 15+ years of accusations that balance was bad, no matter what they did.

If someone scores a 3 instead of a 1 on a scale from one to ten, it means that they improved - but their final result is still below average.