I can't contribute to the discussion cause I didn't have the possibility to read the End Times' fluff, but I wanted to say
@details ' pic is BEAUTIFUL. I guess it's from the Seraphon Battletome, right?
If all the images of the tome are as stunning as this one, this volume must be amazing!
I guess it's up to personal expectations:
I, for one, can't really enjoy these pictures much; proportions, anatomy and perspectives are all over the place, but, above all, there's a serious and visible problem of deadlines and investments when someone notices the copy pastes and the lack of details in forms.
and even the actual good artists with potential to make truly stunning works suffer from this, sadly.
I consider almost all* of these to be FFG tier, simple, illustrative, but not evocative.
but as I said, it's a matter of standards and expectations, I'm comparing them with the peak that were 6th and 7th editions.
*the few artworks that show a good hand behind (in the age of sigmar in general) seem to be from Paul dainton, it's easily recognizable:

this one is from the khornate battletome
of course there are a few others that stand themselves above the average AoS artwork: the one of the slann and this one, just to cite a pair of examples from the seraphon battletome, but they suffer from lack of details a bit too
then again, judge for yourselves:
http://m.imgur.com/a/V9AGb