
It does seem more dynamic than “get six pieces of Tal Rasha’s to have the meta Sorceress build.” I have liked sets in games like this, from Diablo 2-3 to The Division, but I think there’s a clear reason they’ve shied away this time.

And we even have legendary power nodes within the paragon system. We have unique items with fixed abilities in fixed slots.

We have legendary items with variant abilities, we have the ability to extract those legendary powers and apply them to other items in other slots.

While I was a little skeptical when I first heard there were no sets, given how essential they seemed in past games, after seeing Diablo 4’s build design and hearing Adam’s answer, I do get it now, and how sets don’t really work within the framework they’ve built here.
