I think the logo looks pretty well done - enough to the point of where it looks legit. Better than a ton of other patch logos, actually. However, the fact that it's only being shown to us via a screenshot of a private youtube video that's only 21 seconds long...yeah. If it is legit, it could fit in with another demon invasion (ie Wrathion showing us what would seem to be infernals raining down), but I'm pretty skeptical.
Either way, nice work on the logo.