How so? It's very easy to hate PoE core system:
- One-accuracy-to-rule-them-all which makes leveling up more important than most of character building decisions you make, fighters and mages
- The universal crit/miss/graze system that makes magic swingy, unreliable and hard to use properly with multiple effects running out in seconds, while others crit for massive damage or stay for half a minute
- The total absence of immunities by design, making even weakest effects as powerful as high level ones (remember how they finally nerfed Slicken?), just packing on top of each other to the point that no enemy, of any class or type, can't stand against them
- Convoluted, unintuitive stats, often clashing with roleplaying options
- Real health and combat health segregation making combat not deadly and not important, and breaking some of the interesting builds (tankomage would last 4 times shorter in adventure day than barb or fighter)
- Invisible, massively op AOO's built in into fast paced RTwP engine
- Trash options in skills and perks that make you combine many underwhelming small options to create something that matters in combat but still looks underwhelming