that stance is so dynamic it's awesome. if you want me to nicpick, i'd say the grass placement is kinda odd, a lil more quantity or simply removing them might make it look better, that's just to my own personal view on making things as close to real life as possible. of course a horse like that will not exist in the real world anyways. other than that, i think it's probably because of the flash, the horns on the helmet might benefit from a lil more touch of brown at the root end of them instead of entirely being white, something ususally seen on painting orc's teeth. From the picture it looks like you used white to add to the red for highlighting the cape which made it pinkish, some miniature painter i talked to suggested mixing more yellow or orange to highlight red colors, but then again, sun faded red does turn pink~ like i emphasized before it's just minor personal taste, put that aside, i think the horse is really well done.
as for 40k, join the Group Build in this section please!!!!! we need more canon fodders for the imperium of men!!!