A lot of their reveals also fell flat. Mostly because of how they were presented. They were basically gameplay clips instead of actual trailers.
Sorry to cut this part out of the rest of your post (I agree with a few bits of it), but this is the main reason why I really dislike what E3 has become. Call me cynic, but everytime I see a CGI Trailer instead of actual gameplay I can´t help but role my eyes, since publishers have shown time and time again that the finished games does not look even close to what is promised. They are great to get hype going, but Nintendo seems to be focused on showing what they actually have and let the gameplay speak for itself, maybe that is why the Treehouse has such a good following.
I know I am in the minority here but trailers do not sell me on games, gameplay does.