Part of the dreamliner pitch is it's supposed to be better for passengers because of the cabin pressure, and... something else, I forget what. Maybe noise?
When it comes to seat width and pitch, though, that's all on the airlines.
The humidity is supposedly also much better, thanks to much more use of composite materials in its construction (corrosion concerns keep humidity much lower on other passenger aircraft). I've certainly heard anecdotally that this was noticeable, but who knows.
I've yet to fly on one so can't claim one way or the other.
