Late this afternoon I was playing with the multi-shot hi-res mode of the new Olympus E-M5ii. After taking some pics outside (first legitimately lovely day of 2015 here in Michigan) I decided for kicks to try processing the 64mp RAWs on my iPad. (I'm currently using the Air 2 model.) As it turns out the latest version of PhotoRaw decodes 'em just fine. So I did my normal tweaking, then saved as 64mp JPEGs. I polished the JPEGs a bit in Photogene, including some USM, then saved the results to downsampled JPEGs. This all went smoothly, no slower (aside from the initial import) than processing the Oly's normal 16mp RAWs. Pretty darn cool!
I've attached a Photogene screen capture that includes some basic data for one of the pics. I've also attached a 20482 cropped version of the same pic.
So…the Air 2 has the processing horsepower for Big Files. It just needs more software willing to take advantage.