In my opinion, the complexity of PoE vs Diablo3 is not even comparable. I played D3 religiously from the day it was released up until about a year ago when the development stopped and every new season was essentially the same as the last. I often collect some poe currency cheap.
Things that drew me to PoE and got me hooked:
You can make a berserker an archer, a templar a caster, a ranger a melee character. You can do just about anything you want with any of the classes. You do have the option to reroll a characters skill points, but it can get expensive so it’s worth doing your research before you start throwing points into the tree. Speaking of the tree.
2. Skill Tree
There’s So much you can do with the skill tree. While the meta slaves will tell you there’s realistically only a few paths that make sense, this game is such that you don’t have to go with the meta to do the content and have fun.
I was initially overwhelmed with the skill tree, because I didn’t realize that the entire thing housed all classes. Yes, I thought each class had their own skill tree that size. Once I understood that wasn’t the case, it was much more manageable. I’m still learning the tree today.
My favorite part about Diablo 2 LoD wasn’t getting to the end game and killing Ubers. It was the economy. However even that got to a point where you couldn’t do anything with your items you’d obtained except say you had them.
The currency in this game is actually crafting material. So as you accumulate wealth, you can do just that and hold onto it all, or (my preference) you can “gamble” it away with the crafting system. It’s a lot of fun and gives a reason to care about accumulating wealth.
4. Fresh content
The number one thing that keeps me coming back to PoE is the static opposite of what drove me away from Diablo 3. In the last year, this game has had a major overhaul of the acts, adding 6 new ones to the game (some layouts/chars recycled, but new acts nonetheless) added a bunch of new maps, and brand new atlas progression system, another big bad to the story line, and (to me) the hardest encounter in the game – Uber Elder.
There are constantly new unique items added that can completely change the way a skill or entire build is typically played, and old uniques get revamped to make them fresh and interesting. Mind you, this doesn’t happen with all uniques, there are plenty you will instantly vendor after the first week in a new season, but there are many that are build defining, or even just fun to experiment with.