A thing to consider with d4 is the maturity of the endgame. A lot of live service games take a while to iron out the endgame experience. D3 only stabilized around RoS a few years in.
Currently d4 has a good campaign and a decent mid game. Late/end game right now is a drag. It doesn't mean it's a bad game, just that blizzblizz need to analyze their telemetry and work on the game systems to give a better feeling for the 70-100 grind.

Edit: forgot to say that I do think currently the game is worth it, I had a blast playing it before I hit the endgame drag. But obviously everyone's preferences and priorities are different. At it's current state I think it's a 70 hour game, not a 1000 hour game. We'll see how blizzard does with each season!