Gearing and drop rates, AH use almost required to progress.

[Concillian]

In D2 you could brute force your way through the game with pots and some patience, even with subpar gear.

True, but cheesy.

Farming for upgrades would make your life easier, but wasn't necessary for the most part. And getting an upgrade was much easier in D2 with the prevalence of cheap runewords.

Runewords were not initially in D2, it was a later addition, and early runewords were okay, as the runes needed for most decent ones were equally rare to a well rolled rare item. The issue with runewords came when they were very powerful and the runes necessary became more plentiful. Then it was just getting to be a community gear handout. That coincided with synergies, as I recall, and the game was pretty lame at that point.

The D3 endgame is totally different. Inferno is a hard gear check, and your equipment is all rares, which are total crapshoots (and the chance of rolling a really good rare is astronomical, just like in D2).

The loot endgame is not all that different from D2 classic. Inferno is, but as I stated before, the way in which it was presented demonstrated a disconnect between the devs and the players. This was clearly the largest mistake made. Devs clearly intended Hell farming to be a considerable amount of time and many, many players pressed into inferno an hour to a day after completing A4 Hell. Something was seriously overlooked in the testing of how to introduce players to inferno. Some kind of keying like the ubers in D2 would perhaps have helped with that.