A large part of the fun of playing Diablo 2 way back then, was that journey of discovery, of trying out different skills, figuring out what works and what doesn't, what's weak and what's strong, what's a trap and what's not, attempting to game the system, all that good stuff.
None of that would have been meaningful, none of it would have mattered, without these elements that, on their face, only seem to cause frustration, but are in fact vital to making character building matter at all.
You have to be able to fail. You have to be able to make mistakes. This is not a rollercoaster ride, and gameplay is not merely a formality.
The only critique I agree with is that the introduction of skill synergies was a mistake, because they were an attempt to fix something that wasn't a problem in the first place. (In response to a critique much in the spirit of this thread.)