Far from their worst. The EFFECT of it might be the worst, but the presentation itself wasn't terrible by any means.
There's really two issues here that are causing a problem. The first is that unlike Sony's and Microsoft's, Nintendo's conference wasn't 90 minutes of JUST next-gen console. Nintendo obviously feels that what they have going on right NOW is more important that one year from now. Nothing wrong with that in a general sense, but I can see where it would cause a problem. The order of events was pretty poor too. Leading out on the GC wasn't the best of ideas at all. Yes a Zelda trailer is great and exciting, and maybe that alone should have stayed last, but the GC games trailer didn't deserve that spot over the Rev. Plain and simple, that alone was a mistake.
This directly ties into issue two, which is what I felt was the most important, a lack of a games reel or preview of any kind. I saw about one frame of Samus doing something, but the report I read on IGN said it was prerendered and not actual game footage. Besides online, the biggest issue Nintendo has is third party support, and if nothing else it would have been great to give us some hard facts about who's on board either visually through a reel or vocally speaking about it, but we got nothing. Oh wait, we did get confirmation about WiFi Crystal Chronicles from SquareEnix, but that alone ain't gonna cut it. This mystery IMO will continue to hurt Nintendo in the long run here.
Other than that, I think what transpired went over well. I don't know if Electroplankton deserved that much spotlight, but usually the games Nintendo spotlights tend to deserve it, so I won't call them out on that. Although I think the simple nature of the game won't go over well with the hardcore showgoers of E3, unless its amazingly spectacular. We'll see what happens with that on the show floor. No love for Meteos? Laaame. PSP fans are creaming over Lumines, so it would have been in their best interest to say "hey, we not only can match that, we can beat it!" But oh well. For the Rev, despite Microsoft's and Sony's conference, they didn't have to blow the load on their system. They stayed away from specs, because if they DO plan on beefing up a little bit (I doubt it) it was a wise move to stay quiet. They stayed away from the controller, which is fine. They stayed away from the SECRET, which is also fine. But those things are only fine when you address the problems of the past and show that they are long gone. Nintendo did that with online, but not with third party relations. Perhaps they have, but them saying nothing = means nothing.