I sort of don't buy that a coating process will only be used on the larger iPad, given that glass is glass (unless the glass for the mini has to be thinner, but even then, I sort of doubt the validity.
Otherwise, I feel like the A8 and TouchID (along with maybe improved cameras/optics, additional wireless capabilities that we never really needed before but will be nice to have down the road) will be the focus here. Nothing to make owners of the current iPad Air feel bad about not waiting for.
I am hoping that in addition to some, if not all, of those improvements, the third generation iPad mini gets a retina screen with a better color gamut as the current retina screen pales in comparison to the vibrant one of the current iPad Air (and fourth/third generation iPads as well).
Otherwise, calling the next iPad Air the 'iPad Air 2' is dumb as is calling the next iPad mini with retina the 'retina iPad mini 2'. For the mini, it's the THIRD generation. Period. First one had an A5 and a non-retina display, second one had an A7 and a retina display; third one will presumably have an A8, TouchID, and a (hopefully better) retina display. Plus, it's not like the iPad Air couldn't also be considered the fifth generation iPad, because it technically is. It'd be the second generation of nothing other than a stupid naming convention.
Speaking of naming conventions, I'm hungry for some 12.2" 'iPad Pro' rumors.