Well, there used to be a page on the GW website where they had the rules for DoW and who could use what, but I can't seem to find it so they probably removed it. If you can get your hands on the rules, you can use them, I think LM had a few choices they could take. The most common DoW is the giant now though. I would keep DoW to friendly games, I don't think tournies allow them.
There also used to be a section on the DoW online store page from Gav Thorpe I believe explaining that DoW aren't listed in the new books because they wanted to leave their options open for adding a full DoW book later down the line. I think that highly unlikely now, I couldn't even find any model on the site. So yes it does seem like they have been thrown to the back and forgotten.