Double black CC and glass jaw suggest that this could maybe be 2BB.

Is it just me or does this seem to want to be either blue or blue/black?

Black's done mill before, particularly with the Dimir in Ravnica. This guy does it a little more aggressively than other black mill options, but for the sake of the set's flavors and how they interact with the mechanics, I feel this guy is justified. Plus, he fills the role of "4/2 black near-vanilla" that so many sets have.

Yeah Dimir were fun :-) (long time Mill player) I think its just been a while since I saw this on a mono black and the mechanic name made me think of cards like Mind Twist & Mindstab Thrull which are discard themed and on first glance at the mechanic name I presumed it did something similar. Nothing at all wrong with the card as is though.

IIRC blue tends to have more direct mill and black more mill with some sort of choice in. But I agree if mindstrike is a theme, it should go straight-up in blue and black, like how infect went in many colours. ("This deals damage to players in the form of putting cards from the top of their deck into their library" :) Which isn't as silly as it sounds, because it means damage prevention and when damage is dealt still apply, but probably still too silly to print :))