And yet the Lord of War is in there, Psychic Powers which allow people to toss Vortex Grenades, unlimited summoning, and so on. I'm not disagreeing with you that the fact that some of them are extremely weird for 40K (and probably busted) but that doesn't mean much when the entire game is equally busted. I agree that it is likely when they get around to giving us a Faq/Errata on the basic rule book (hopefully soon) that it should include a clear notation on which Formations are allowed and which are not either by individual entries or entire publications. Currently, there are Games Workshop Story Managers using them and when I wrote Black Library about it they forwarded my question to the rules team. The answer that came back to me was "a formation is a formation." In typical Games Workshop style I'm not even sure they did more than skim my question.