There's no way to make their stuff so unique that no one else could produce similar models. It'd have to look unrecognizable. GW did their own style of Orcs and Orks. Now you can get that same style from multiple companies. Will it really change with "Orruks?" Heck no.
Also, I'm not sure other companies should be called "coat tail companies," unless we can also call GW something similar, because GW got its start by making stuff for other people's games.