They have a sort of grey skin so that it will look more like 'mongolian', since thats what it's based on, right?
'The Maw', the ogres god, has existed in warhammer for quite a while according to those who have been doing roleplay warhammer. So they're not entirely new i guess.
And has ANYONE complained that chaos dwarves used greenskins? They have both hob-goblins and black orcs.