What exactly was new about the Necromancer? The majority of its effective builds are based around abusing a 2 minute CD. That’s not new - the Wizard, Barbarian, and Crusader had been doing that for literally years before the Necromancer came along.
As far as strategy goes… freezing everything on the screen is a sign of how degenerate strategy has become in this game. They’ve gone so far in the wrong direction that the only way to survive is outright negate everything that can be done to you.
And for every one who likes the Necromancer, there is another one that doesn’t because you can’t do what you could in D2 with it. Guess which classes people want brought in next? That’s right - the other D2 classes.