I know that a lot of people merely pretend to look forward to the "death of grimdark", but I'm still concerned by the way people tend to circlejerk over concepts like "nobledark" and the idea that 40k "shouldn't take itself seriously".
Cause to me it sounds really dumb; I often see people who want 40k to have a "nobledark" tone (a tone that emphasizes heroism) but are also firmly convinced that it should be kinda silly, and that the grimdark tone that was very prominent around the 4th ed is somehow detrimental to those things.
I think it's flat-out wrong, I think that 40k has always been grimdark, and that in order to have some humor, and some heroism, it NEEDS to be grimdark as fuck.
Cause here's the thing: if you remove the unreasonably evil characters and all the horrible things from 40k, you suddenly have a lot less to make fun of, and coincidentally, a lot less material for heroism.
In fact, 40k hero-wank really began around the 4th/5th editions, where it took itself seriously enough to give all its characters an over-the-top backstory that allowed for stuff like the Spiritual Liege shit.
Of course it isn't as goofy as stuff like 'Ere We Go, but if you want to look back upon the Rogue Trader as being more light-hearted, you also have to admit that it was grim as fuck; in a less dignified, more punk way, but still really grotesque and fucked up, and that's also when you had stuff like the Inquisition War trilogy and the weird fetish shit from the Space Marine novels.
So humor and heroism aren't hindered by grimdark, they thrive on it. If you make 40k *nice*, then there's a lot less opportunity for dark humor on the one hand, and for dramatic weight and grandiose visuals on the other. If you make 40k *nice* you end up with milquetoast, vaguely cute tumblrish nonsense like Eagle Ordinary, Emperor TTS, and narratives that sound like some random Justice League arc.
And you might as well drop 40k altogether to jump into the Overwatch fanbase instead.