[pulmo]

Right. And people will ask themselves ... why have I paid more for a heavier notebook?

[dagw]

I imagine that a 12" retina MBA will mean the death of the 13" MBP. I further imagine that Apple is perfectly OK with that.

[XorNot]

I'm really struggling to imagine customers are going to be ok with that.

Just because a smallish form factor proved propular doesn't mean you're not suddenly going to find a size which is a dealbreaker.

12" is tiny and doesn't really improve portability for a laptop-like device (which goes in a backpack).