I have been playing Path of Exile a lot. It has been described as the spiritual successor to Diablo 2 and after testing both Diablo 3 and POE I definitely agree with that description. D3 has its own charms but POE definitely *feels* like D2 and honestly seems like more fun than any of the games that actually bear the Diablo name. The funny thing is that a lot of the things I find I most like about POE are things that were specifically engineered out of D3.
In particular I like that I often have no idea what is going on. When I finally went to kill Piety at the end of POE I honestly didn't have any idea why I was doing that. I knew she had shown up and mocked me once or twice and definitely killed a guy once but other than that I really didn't have any awareness of why I should bother. This is definitely the sort of thing that happened in D2 - you could end up fighting nearly all of the act bosses without really knowing why aside from Diablo himself. D3 very deliberately had the enemies pop onto the screen to mock you and tell you their plans so that you absolutely could not fail to know what you were up against. It turns out I really like being able to just wander around butchering stuff with no clue why. Of course if I really wanted plot I could go around to everybody in town and hear all the speeches and get all the backstory but the wonderful thing was how optional it all was.
That optionality of various parts of POE is absolutely key. I am completely able to skip quests, wander into zones for no reason, ignore lore, and just do whatever the hell I want. There are gates to progression of course but they aren't always in your face and they fit nicely into the world. A truly open game with no direction isn't really what I want and the utterly regimented plot of D3 was stifling but this middle ground with some plot that needs to happen and a bunch of stuff you can do or not is fantastic. I think D3 was deliberately designed to avoid the scenario of the player having no clue what is happening, probably because people ended up wandering around in D2 being completely clueless about what to do next some of the time. Unfortunately that choice really makes the game feel less like a series of interesting choices and more like Progress Quest.
The loot decisions in POE are also absolutely fascinating because sockets and gems are just so damn flexible. A piece of gear has not just a series of random properties but also a random set of sockets with random colours with random connections. All of the dimentions offer incredible variety and make gearing choices very complicated. Do I want to wear the gear that lets me socket more stuff onto my primary attack, or gear that gives me more resists? More movement speed, or another aura? Can I afford the loss of mana? So many questions! More options, both to be bad if I want or awesome if I can figure it out, make POE by far the game for me.