The trailer certainly was "unepic" when compared to the other big guns Nintendo pulled out. Goldeneye 007? New 2D Donkey Kong in over nearly 20 years? New Kid Icarus in WELL over 20 years? Skyward Sword and the new graphic style just couldn't compete with that, especially when they were shown first. I think this proves that Nintendo wasn't trying to blow away the conference with Zelda; it would've been last and much cooler if they wanted to.
Which begs the question of why. Why was Zelda first, and especially why the graphics change. First and foremost, I think they knew they just couldn't do it with Zelda this year. New graphics that depict the lightheartedness of WW combined with little more that a showoff of new motion controls.... What else was there to the trailer? And even then, no "epic" battle scenes, no hint at the story and its significance, just......nothing. I am NOT saying this plagues the game in ANY way though; it just means Nintendo never meant for Skyward Sword to blow away the crowd this year, and they knew why.
Graphics change is just a result of gameplay. I've stated this theory many times before, the Nintendo stems both graphic style and mood off of the given gameplay the need. Example 1: WW, the first game to radically alter the graphic style. Why did Nintendo do this? Did they think it would feel "more Zelda" like so many people claim? I don't think so; why have TP right after that. No, I think it was because of the gameplay Nintendo had in store. For instance, all of that water. Could it have all appeared in TP's style? Of course not, there's just too much of it for it to work. So why not create it as a massive blue wall? That would sure be possible. This combined with other needs would have lead to the creation of the WW style, and the light mood of the WW would follow with it (I won't dive into that aspect of my theory in this post though).
Example 2: TP. Another radical change, especially considering what WW was. This time, no dramatic changes would be made. Nothing special gameplay wise would be added, no massive amounts of water, and nearly no change to the setting when compared to OoT (of course, in the way that the concept, e.g Death Mountain and Zora's Domain, were already present). Why not go wild with this one? We don't NEED the toned-down graphic style, because the desired GAMEPLAY doesn't require it. Hence, the style of TP was born, which in a way I would call, "just because they could, and it's what the fans wanted." Mood would follow (again, another post for another day).
Example 3: SS. I would hope by now that it's well known that the graphic style wasn't chosen just because they liked it better than other options. No, it's been stated that graphic style was stemmed off how to make the motion controls work; another gameplay aspect. SS works in the same way as WW in the way that the graphic style HAD to be used in order for the gameplay, which has always been first priority, to work. I take this confirmation as hard evidence that the graphic style of a Zelda game is first and foremost determined by the gameplay that the developers want to implement in said game. Mood, once again, will follow. I expect a WW esque mood, given that the trend since 2002 continues.
So yeah, that's my explanation of why SS took the backseat of E3 and why the graphic style is there in the first place. Could be wrong, but given Anouma's exact quote concerning how the graphic style of SS is intertwined with the gameplay, I'm starting to believe it as cold fact too. Makes me feel better to believe it too; the change in graphics has made the Zelda series look even worse in the eyes of the gaming community that's outside the Nintendo fanbase, and it would really hurt me to find out this is the only style the Zelda series will offer from here on.