Not that the 3DS is that comfortable, but the 2DS looks like it would be just plain painful to hold onto for long stretches.
It's a bonus that the weak hinges are gone, but it comes completely at the cost of portability, unless they assume that things like the iPAD are considered portable despite being relatively large.
I personally enjoy using the 3D on occasion, but it isn't integral to my experiences, and more often than not I find the way they use the 3D either ineffective, or worse, distracting from the game experience.
I think it's a smart move by Nintendo. Continue enlargening the consumer base of their profitable handheld system by releasing a lower-priced model that takes out some bells and whistles. People need to stop bemoaning the fact they aren't using these resources on the Wii U, as every good company diversifies their efforts to work towards a profitable situation.