Yup, shades rotation is on the roadmap: https://github.com/klimeryk/dealwithit/issues/30. Hope to get it done some time today/tomorrow. Most pieces are ready, just need to figure out a good UX for the rotate handle. Worst case scenario, it can be also an input field.
Background photo rotation - could you share what would be the use case? The output would be a bit weird, since it has to be square, so either it needs to be cropped (so now there needs to be crop feature ;)) or there will be blank spaces. Honest question, I might be missing some interesting use case! But hopefully, rotating the shades would solve for most of these.