This is not Planar Chaos-ly, not anymore at least.

Black now frequently gets cards like Zombie Apocalypse, Crux of Fate, and Bontu's Last Reckoning.

The nonartifact clause is a bit Time Spiral-y (as in the set, not the block).

Yeah. It's in the current black colour. The main goal overall goal is to give black creature board wipes and not give them to white (which a change in the planar chaos colour pie). Except showing an absence is hard until you get a complete set.

The notartifact clause is supposed to be topdown to the card as artifacts don't have flesh to stripped away. This and the skeleton tribal are supposed to be planar chaosy. (black removal kept it's weakness to artifact creatures and skeletons are now the default black race instead of zombies. These are two roads that magic could have taken but didn't.).

The major dilemma of this set is to risk either sticking to closely to the colour pie and being overly conservative or making to many bends/breaks.