I've used lye-based solutions to remove anodising on a number of cranks. It's a process that you have to monitor closely to pull and rinse the item so that the base metal is not affected. Sanding and polishing is a chore, but results in a nice shiny finish. For cranks, this is also a good time to inspect for micro-cracks.

I doubt that the caustic bath affects the crank significantly (any more than the acids used during the anodising process). I have also heard that sand-blasting alloy cranks results in work-hardening that causes brittleness. I doubt that this is significant, either.

Decide what you want, and then do it.