Well, Dragon now says Official on it, so I guess that it is official now. I imagine Wizards would consider anything they have published official, but it really depends on who you ask. Personally, I take it on a feat by feat basis. Players are alloud to take feats from any source or even create their own, I just have to approve it just to make sure it isn't over the top or too weak. If it is one of those things then I offer to help them adjust it to something reasonible.