You have elves, dwarves and faeries, how could anything with all that be Grimdark?
Look at 40k, same thing minus the fairies, although who knows there could a race of xenos that look like mini humans with wings.
P.s. you forgot Kislev to the north who hold of most of the land bound chaos warbands. The main differences between 40k and f is that there is only 1 major threat, chaos while sure orks, VCs, and druchii are dangerous they aren't a major. Orks are more of a nuisance now, VC atleas the Carstens are to busy trying to stab each other in the back, the druchii are more of a trade/ coastal threat. Last but not least the 'good' races will actually stand together, unlike 40k when things have to be damn desperate/beneficial for even an eldar or human to help eachother.