I love the texture of these , my unreal folder is just full of rocks and cliffs. 
Only one thing for me i would not make the large pile of stones so smooth , there would be 
a few more edges sticking out , the pile could do with a bit of random ones stick out in different directions.
But really great work ,well done.
As i said thats just me , you keep doing what you do.

Thanks for the comment yeah, it depends on the art direction stay tuned for more renders of my Viking project