Modern video editing has come a long, long way since the days of Newtec's Toaster. Everything these days is digital and in that arena I suspect AOS, even with all the improvements of MOS or AROS or OS4 would be put under severe pressure to cope with the sorts of demands that kind of software would make in today's environment.
Photo editing is probably more realistic, but then you're competing in an arena where Linux has some pretty mature and feature rich software to choose from.
I'm inclined to think Video editing will be the easier of those two. Modern chips include hardware video encode so unless you're doing some heavy video processing you don't need that much power. The previously mentioned Pandaboard has 1080p hardware encode.
OTOH The big problem in photo processing is you need ever more powerful hardware to handle ever more megapixels. I bought Lightroom 3 a while back, I promptly upgraded to a Core i7 machine to run it! Heavy processing on 21MP images requires a LOT of power and no Amiga flavour has that.
BTW 21MP may sound like a lot but you can get 12MP in phones now.
Amiga coming back was a great dream in 1997
Come back? It was never big as a desktop platform.
