Aside from the gaze mechanic, the tells in M7 are standard fare (seeing past a gigantic boss model notwithstanding). The difficulty comes from running around the arena on cue, and in that respect, I'd say that M6 is easier here just because of the distances involved.
In my experience, it's M5 that consistently racks up the body count. M8 seems to suffer from lack of Slice is Right experience and that some folks don't quite grasp, "it's always: he teleports to the edge, dashes through the middle, and then does a conal cleave; so stop running to where he just teleported."