i look at the passive tree as more of a fleshed out way to distribute attributes, which IMO has never been very satisfying in any game. you put a couple points in strength, vitality or whatever the game's primary stats are and don't feel stronger. the difference in PoE being that the major nodes and keystone passives (the ones that completely turn your character upside down) actually are satisfying. getting a 10% life increase or having all of your character's evasion rating turn to armor feelsgoodman.jpg
to each his own, though. from what i've played it's basically as close as we will get to a diablo 3 without a direct sequel from the old blizzard north. i especially love the skill gem system and how you can link it up to different support gems and make your spells utterly ridiculous. i'm looking for chain, fork and multi-projectile so that i shoot multiple fireballs that chain between enemies (like chain lightning) then fork into different directions. the loot is very similar to diablo 2 as well, but like diablo 2 it takes a while before you start finding it. my biggest complaint is the low level melee combat can be pretty floaty and sluggish, but after playing diablo 2 for so long i'm kinda used to melee starting out slow then becoming really fun later on. oh and the lack of animation cancelling makes certain spells without a lot of FCR feel clunky and slow.
i can't speak to how much its changed as i only started playing earlier this month, but so far it has me hooked. keep in mind that i say this as someone who didn't like TL, TL2 or any ARPG of the past decade because they weren't as hardcore or similar to D2 so to what credibility i have in a suggestion is dependent on what you're looking for.