There is something very strange about the way people say they feel about retina displays. Unless it's a side-by-side comparison, I can hardly see any difference between a retina and non-retina screen on a full-sized iPad (and we have both in the house), so I certainly can't imagine it could matter on a mini which has a smaller screen and looks great to me.
Nonetheless, there are plenty of credible people posting every day about how they have trouble reading type on a non-retina display, or that once they'd gotten used to retina they can't abide anything else.
I'm really no longer persuaded that it's just hype or psychology as I first suspected, but that it must be something different about a person's eye or visual cortex that accounts for the divergence.
I don't suppose we're covered up by ophthalmologists or neuroscientists on this thread, but it would be interesting to know if there's been research. Or educated guesses.