The PSP nub had a lot less to do with the placement and a whole lot more to do with the "sliding disk" design, which was just bad.
If anyone wanted to bring ergnomics into a handheld discussion, they should probably start with the DS line and its hard edges and block-like form.
Seeing as how no one has used the NGP for any extended period of time, I'm willing to give it the benefit of the doubt until I do in terms of ergonomics. As for the thumbsticks, they look like thumbsticks that pivot off one axis like a regular stick and early reports from those who used them have already gone on record as saying they feel great to use.
Ergonomically, the NGP will likely be the most comfortable handheld as it was designed contoured with smooth edges to conform to the hand, complete down to finger wells on the back for grip.
