Yeah, I am stunned they did this before the movie. I think, personally, that sub and participation numbers are actually so low that they felt these private servers might actually be "stealing" subs. Doesn't seem they though this through at all.
A better idea (since Blizz does not want to do vanilla servers themselves) would have been to work with nos to provide a better experience for fans of the franchise.
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I do agree with you about descretion, if you are doing something that is technically illegal , it is best to not flaunt it.
This whole thing has left me with a negative view of Blizz though (even though I don't play on private servers). I know it was their legal right to do this. But, they refuse to offer "legacy" servers. The fans have been asking for them for years. Another company offered them and about 150k players were having fun playing them. Why bother breaking it up?
Also, compare the private server thing with "buttgate." People have been asking for private servers for years. Blizz has not budged (so, "surprise" the players went elsewhere). People complained about Tracer's pose and it was changed pretty quick. Hmmm. Why listen to one group and not the other?