Bryan Fuller posted this on Instagram as a birthday greeting to Laurence Fishburne, back on July 30.
So apparently Fuller had intended to carry over the Hannibal cast into Discovery in various parts — and this was how he'd imagined Fishburne in Klingon prosthetics. It also suggests that the much maligned Disco Klingon designs were decided upon after Fuller left as (preliminary) show runner.
ETA: Here is a rundown of the casting plans he had in mind, originally revealed on the D-con chamber podcast. I would have watched Gillian Anderson as a starship captain.
Most Black people aren't, like, midnight black. They're varying shades of brown. Most of these Klingons are in the "Black human" range of colour tones, just with less saturation and a purple tint. They look black to Me in the same way that most Black humans look black.
I don't think grey or purple are within that part of the spectrum at all, but I doubt we're going to find an agreement on that one.