PoE 1 had some rather fiddly systems, but I felt like most people could wrap their heads around what deflect did, for example, or that a larger shield was going to make your character survive longer but deal less damage, which had some value in the resting system.
Where I had a complaint was that the actual Armor itself was sooooo fiddly. With like a basic armor rating, and then how good it was vs Blunt/Pierce/Slash/Corrode/Ice/Whatever else.
It’s true that if you were playing on Normal difficulty you could make it through ok just kind of putting on whatever seemed appropriate for the character, and be just fine. But god help you if you were interested in playing Path of the Damned and you didn’t really love memorizing all the damage types of every enemy and matching up your front line in appropriate gear before almost every battle.
I feel like the battle difficulty could have come more from overall strategy and less from inventory management and memorizing damage types vs armor types. And of course a fair bit of the difficulty did come the overall strategy and your skill management. But I could have done with a lot less of the nitpicky armor stuff. Hey, that’s just me. If there is less of that element in PoE2 that would be great.