As a photographer who's come from the now-deprecated Aperture, through the horror show that is Adobe CC, and finally settled on Capture One for photographic editing and cataloguing, I've found consistency of support to be the utter bane of my workflow – from waxing and waning RAW support to ever more tepid Wacom drivers, my Mac is becoming less and less a viable option for editing (let alone on-the-go) and cataloguing.
Given the challenges in maintaining a library under a single umbrella, as Pixelmator doesn't attempt to touch catalogues either on mobile or desktop, I'd love to see RAW support in Pixelmator Mobile. This point is furthered by the native iOS 10 support of most common RAW files for import. Moreover, the ability to edit RAWs and export the edits as unflattened layers for other editors' use would push Pixelmator beyond any other offerings on either desktop or mobile, allowing for a cohesive mobile-desktop workflow. This feature alone, I know, would be cause enough for photographers everywhere to push into mobile and buy Pixelmator.