The Nook HD isn't as thin as the iPad Mini but it's shorter in length and breadth. And the Nook HD is promising similar battery life to the iPad Mini (9 hrs versus 10 hrs) and similar weight (315g versus 308g)! Would people really have minded if Apple had got an iPad Mini retina at the same thinness as the iPad 2 (8.8mm) which is still noticeably less thicker than the iPad3/4 (9.4mm)? The iPad Mini is just absurdly thin (7.2 mm) and I think a retina display would have been the better tradeoff.
I'm not saying people wouldn't have cared. I was just saying that Apple probably cared. Hey, I'm one of those people that happily gave up the ipad 2's weight and cool running temp to get a retina display as soon as I could.
And although I agree with you about the nook screens being higher res and not needing bigger batteries, they don't have the same number of pixels as the ipad 3.
I think we need to look at what happened between ipad 2 and ipad 3 to infer what the 2048 x 1536 res might have done to the ipad mini. yes, the size is smaller so the backlighting wouldn't have been as massive, but it's still driving an insane number of pixels and the only tech Apple has shown for the display still requires some really
bright , power hungry backlighting.
If they can move to a new display tech that requires less backlighting and is overall lighter and thinner, then well see it in an iPad mini.