I've been playing it. To the contrary of everyone else, it was the leveling/campaign that sucked for me and the game only got good in the endgame.
There is no challenge in the game at all until you ding level 60 and beat a tier 20 pit to unlock torment 1. After that the seasonal activity this time is actually fun, the borrowed powers are cool and easy to grind, and the gear chase is pretty fun. There are lots of viable builds on my rogue so I've been having a blast. To each their own. I just started playing for the first time at the end of last season. I also loved D3. D2 feels a bit too slow for me but back in the day it was my goat.
I doubt I'll be playing it for a year(probably more like for another couple of weeks), but maybe one day I'll play the next xpak. I got about 90 hours so far and they have been a good fun 90 hours. Well worth my 40 or 50 bucks for the game+xpak. My rogue and spiritborne are also super hot and half naked women so that helps.
My xpak came with 2 level 50 boosts in the eternal realm I think, which when applied let me skip collecting alters of lillith even on seasonal, so getting that head start on the season collection also felt good. I'm currently running a 140 paragon flurry rogue that uses the frostburn gloves for CC. Super fun stuff and I made the build up myself!