I'm surprised that Nintendo didn't do something like it sooner actually. Especially after some of the bad conferences that happened. I guess when the conferences were good, it was easier to forget the bad. Yet, I have a feeling that if Wii Music had been debuted and shown in a Nintendo Direct or Digital E3 type video, it probably wouldn't have had such a negative perception and instant loathing that it got from being shown at a traditional press conference.
Instead of having a group of people come on and force enthusiasm to be playing this game at this moment for an awkward moment, making a game appealing is much more easier and simpler by the way it is done now in Nintendo Directs and E3 Digital Events. Insanolord mentioned the Skyward Sword technical issues which is another thing that can crop up even no matter what the quality of the game is and is another example I was thinking of where it instantly starts creating a negative impression in the audience's mind as the presenters start struggling to keep the momentum and enthusiasm up.
Frankly, an E3 presentation is usually just some live commentators talking about a game and then throwing the audiences attention to a brief video of said game over and over. Why not just make it all video? That said, I am glad to have the moment of Reggie immediately exiting off stage after handing it over for the Wii Music performance as he makes sure to not be seen anywhere near the giant bomb about to be unleashed on the audience. Classic stuff and it always makes me laugh.