I'm not sure I'd call it a curve.

Small phone vs. larger phone is a very simple tradeoffs calculation.

Large phone: good screen, bad ergonomics Small phone: small (thus worse) screen, best ergonomics

I'm willing to pick the second option above.

Unfortunately the Mini is somewhere in the middle: smaller screen than the larger phone - thus worse in that aspect -, combined with worse ergonomics than an actually small phone. It's the worst of both worlds.

I don't know about other things, but ever since the iPhone 5 I've been wanting another model that I could use with a single hand. The Mini was never that, so why would I sacrifice a good feature (larger screen) for... nothing in return?