No he’s right. Grinding to 300 in D4 takes slightly less time than grinding to 99 in D2, only due to the fact we get exp buffs in D4. Both are horrible grinds though and typically not worth it to the average player.
Gear progression wise D2 is worse. Although I already know people are going to argue against this. I’ll just say I’m fairly certain they don’t remember just how many boss runs they’ve actually done in that game, or the variables each item could potentially roll.
D2 is definitely a product of its time. It set a new standard, but not all of that standard should be kept. Stamina bars anyone? The list only starts from there.
At its core though, D4 does follow D2 quite a bit. Whether or not people want to admit this is another story.