Nintendo didn't exclude 3D from the bottom because they were lazy. They explained during the conference that touch screens and 3D screens don't really mix at all.
I'm not sure I agree with their reasoning on that. Why is Sharp mass-producing those parallax barrier touchscreens, if the two technologies don't mix well? Besides, don't most people uses styli, anyway? I don't see that smudges and whatnot would be much of an issue.
However, I can live without 3-D on the bottom screen, even though I believe their reasoning on that was either flawed or misrepresented (the real reason being simple cost). The lack of a bottom widescreen, though, is a major gripe (my only gripe, really).
QUOTE(Midna @ Jun 15 2010, 11:42 PM) So they settled on one of each. I'm slightly disappointed at the bottom screen's lack of widescreen, but it's not that much smaller. It'll be used for the touch elements in games and the top will be used for game play. And for those who were talking about sprawling cutscenes between both screens, you should probably remember that the bottom isn't 3D anyway. How would a half 3D half 2D cutscene look?