I like D2, I like D3, and I also like PoE and even Victor Vran. Grim dawn also quite decent.
All have good and bad points. Obviously everyone & their cousins have opinions about what is best.
It’s not an easy balance to satisfy people who want deep games and people who want casual experience. People who want the game to be competitive with the leader board, people who do not, as it forces people to play meta build for instance.
Personally I prefer leaderboard even though I never competitive and not obsessed with playing the most meta build.
Obviously your build needs to be somewhat competitive or you can’t find people to play with you or if you solo, it matters not much.
Depth is harder to balance, having much stuff does make game more complex, but not all complexities are meaningful. For instance, PoE has many modifiers and mechanisms that I think excessive, like accuracies, CI and low life energy shield. If you make an energy shield build, you look for items that enhance energy shield as oppose to life or armor. It makes sure people wear different gears and look for differences stats, but add zero to the gameplay.
Also, physical attacks were treated differently from elemental ( ice, fire, lighting) and again different from chaos damage. Armor only protects physical attacks, elemental resistance only for fire, ice and lighting, and chaos resistance are rare on gears with low value. Also, armor reduces damage by fix value while resistance is by %. Complexity for sake of complexity.
There are however good complexity, if you want to have high block chance, high dot damage, there are many skills, gears to enhance it. In D3? Is there even a single item that enhance DOT?