The announcement came as a surprise and has created a lot of buzz throughout the gaming media and community so it seems to have been a pretty good move on MS's part.
I agree with you in principal, but man that show is a slogI think the timing on a grander scale is fine but I would have set it as the final segment of the show.
As someone who didn't watch TGA, the Xbox X reveal was one of the only reveals that I cared about. I think it was a good move.
I like big surprises with no previous leaks. Hellblade also was perfect to showcase the new console. The trailer screamed awesome next-gen tech, it was explicitly NOT one of the usual suspects Halo-Gears-Forza. I didn't like that the audience reaction was not really transported well through the stream, as I saw some live reaction videos. I didn't like that the cut to Geoff was pretty abrupt. The reveal should have ended the show, IMO.