A very high value is placed on bypassing mob resistances, and it comes more naturally to magic builds than to stamina builds. As it currently stands, stamina DDs put a lot of effort into getting 18k penetration. All other stat options are simply laughable up to that point because the pieces that offer physical penetration are 30% stronger than similar pieces with weapon damage, stamina and crit. But why does that have to be the case? Sharpened got nerfed but now a lot of Stam builds are taking up another resource to get to 18k phys pen.
All the classes across the whole spectrum of the stam meta seem to be using the same 2-3 sets and it likely won't be changing with this update. I understand that WD, Stamina and Crit can help with healing skills, and that may explain why they have a lower impact on damage than penetration, but it still seems lopsided. The options that add up to 18k penetration are still few and they dominate their respective slots in our builds.
This is just my opinion, but it would be nice if resistances were tweaked so penetration really only had to be stacked up to 18k in trials. Give us 4 person dungeons where bosses are like what you see in Maelstrom Arena, they're different with varying resistance, not all of them and their minions have 18.2k armor, just a few. This would promote build diversity, I think.