The sheer fucking hubris of it all. The unexamined and unjustified hype wave. The "influencers" peddling the damn thing with naked cynicism. The recycled maps that often just took the same assets and tilted them sideways. The laughably bad QA allowing almost anything to be put in the chat box.
The way it just... stopped being relevant.
That is all. 
The fact that it was profoundly racist to the point where they brought in an outside consultant to help make it less racist
And it was still very racist
What if conquistadors!... but there's a vague World of Warcraft "corruption" cliche.