I wrote my own diatribe on this very idea, coming to the conclusion that Apple might use it to resurrect the Aperture branding and bundle it with Final Cut and Logic for an all-in-one 'Apple Pro' subscription.

I never thought about baking it directly in to the OS though! Thats an incredible idea, having it pop up in Preview or upon taking an iOS screenshot. They could even go as far as using the word 'Pixelmate' to evoke its commands, removing the 'Photoshop' verb from vernacular.