As EP1 sold out and An Omen came with Secret Free Vinyl™, pre ordering WO made sense to me. Basically the only purpose is to put money in the artist/label's pocket pre-release, and to encourage sales in a wider time frame. The word "preorder" is in itself a tautology as all orders are preorders (you don't order something after you get it after all).
Communication is they key in things like this though, if there were exact reasons for issues, a more detailed timeline etc, then it'd be less irritating.