Hi , My directory received some submissions in which the web site is one page only .Most of them is promoting a product maybe an e-book or some health food .... If your a directory owner , what is your point of view to those kind of submissions ?
Nor me.Or sites "under construction".If people come to trust your directory as only listing quality sites they'll maybe come back.
I notice that you said "most" and not all so...... Depending on the quality of the content I might add a single page web site. It would have to be exceptional for a single page; product information, links to quality resources, reviews, etc.. If the page would be of use to your visitors and enhance the quality of your directory, it might be worth another look. Check and see if there are any quality inbound links from other sites. If it's pretty crappy, I wouldn't accept it.