I am reminded of a quote from the Diablo 3 development team prior to launch "and then we doubled it". At the time they were referring to how they made the highest difficultly level insanely hard to make sure everyone would die. First they made it hard, and then they doubled it.
Doubling it was a terrible idea, and they screwed the difficulty curve up horrifically.
In the latest season they took most of the best sets for all classes and doubled them. For my favourite class, the Witch Doctor, they increased the overall damage by double on the set, then added an extra 50% on top of that. They they gave me 20% damage reduction, 15% elite damage reduction, and reduced the damage scaling in higher rifts.
The game sure feels different now. Instead of treasuring each new level I get I end up levelling 9 times in a single run, and I do that in a rift that is so easy I beat it with half the time remaining. It is almost an absurdity compared to the heinous grind that the game was at release where you would have to put in 100 hours to see any notable increase in power.
It is still fun, of course. Mowing down monsters is a good time and the game scales infinitely so eventually I am going to hit the point where it gets hard. But all these nerfs and buffs compound in powerful ways. Although I do 3x times the damage of last season, that means I can go up 15 rift levels, which increases my XP gain massively, ranks up my gems, and gives me better loot. Which means I go up to higher rift levels, etc.
However, you can't look at any numbers from last season and have them make any kind of sense. I don't quite know what to think of it, really. It seems almost ridiculous that gems have a level 25 ability, as though that is a challenge to meet. These days that number should be set at more like 65 to be of equivalent difficulty to when gems launched.
I guess the real metric is "Is D3 fun?" and the answer is yes. Smashing monsters to pieces is great, there are tons of crazy and interesting things to do, there are actually a lot of choices in how you build a character, and I have fun with it.
They finally have the game in a place where casual players and hardcore players play the same game, just with different numbers. And that is a good thing, I think.