As the title says, I realy don't get it?
Exclusive skins for pre-orders, but you can get only one, they don't seem to be unlockable? Are they?

Standard skins are not bad, but there is nothing special about them, and nice (yet a bit underpowered) weapons such as the Grendel have only one skin? Was it too much to ask for?

Anyways, Since the game is already dying nobody will care in a near future, but it's a shame.

Here are two pictures of a skin only few will enjoy, I don't have it, I just picked it up from a fallen foe.