Even making it members only to view won't save us legal troubles
We can STILL get in trouble, remember Wind-up? So your argument of "can't use fair use" should really mean we can't host ANY amvs that use whole songs, and allow them for download or viewing for members or no.
As for ratings, just don't allow non-logged in people to rate anything. Simple as that.
I don't think it's too much to ask people to log in either, however it would be advantageous for some people to be able to share the link without having to tell someone that they can only view the video if they sign up. It would be convenient, and easier.
We also don't need a bunch of dead one time accounts created by people who only came to watch one video.
If the person who has the videos shared with them wants to sign up to gain more advantages such as: commenting, rating, creating playlists, downloading, participating, (just like those youtube members you mentioned) then there is nothing wrong with having people create accounts to participate. No one ever said anything about letting non-members have all the advantages of members, just allowing non-members to VIEW preview versions of videos.
As for people hosting here and taking the discussion elsewhere: I already have seen plenty of people do that. So, I highly doubt that making previews available for viewing will change that pattern of behavior. If people don't want to participate here then that is their choice.
But we don't have annonymous reviews here, so those editors won't be getting the feedback they're used to, so what's the point?
Eeeeh wut? Since when does Youtube have anonymous comments? I think you may have that backwards... or something was phrased wrong O.o
Besides, I wish we would get rid of anonymous comments we have on here anyway, but that's been my stance from the beginning of QCs.. I've been pretty reserved on what I really think of QCs.. but to put it mildly, they hold no weight to me when compared to a review left through the op system which links back to the person who left it. Youtube comments hold more weight to me than the QCs here.