For people complaining about the folding, I was under the impression that since 2DS is geared at children (since their eyes are more vulnerable to the side effects of 3D), they decided to also take away the folding for them too. I can understand why it might seem kind of stupid, since it makes the screen more vulnerable to scratching since it's always exposed now, but at the same time, it sounds like kids are pretty reckless with the hinges on the 3DS (at least from what I've read on some sites, though I find the hinges pretty durable). I guess Nintendo figured that it's better to just get rid of the hinges all together so the kids won't be able to break the system quite as easily.
I definitely understand kids being pretty reckless with the hinges though, because their curiosity gets the best of them, especially if the kid brings it to school, and they let everyone touch it and such to show off. It's like getting a new pair of those flexible glasses and letting the kids at school touch them to show the glasses off. Those kids WILL test the limit of those glasses and end up breaking them.
And besides, I don't know if a regular folded 3DS would even fit in a child's pocket anyway considering their clothes are so small. They'd probably end up putting it in their backpack or carrying case of some kind whether it was a 3DS or a 2DS.