I'm not a professional photographer though I have done some paid gigs in the past and I fail to see how Lion greatly alters your work flow. Please provide some details as what works in SL works in Lion.Lion has seriously affected workflows in so many areas, my productivity as a professional photographer will take a nose-dive in so many ways if I abandon SL;
& no I do not need Rosetta, Rosetta is not the issue at all.
That is, I easily import my images into Lightroom, cull the keepers, categorize and keyword the images then move on to editing and outputing (if needed).
I do the same exact steps in Lion as I do in SL
OP, you're at a point where the hardware has changed significantly and so you if you want to run Snow Leopard the only option is to stay on older machines and not buy a new Mac.