I have probably a thousand ratings and I know they are allowing a PDF export of your history and ratings. If I could find the right service I wouldn't mind spending a rainy afternoon or sick day migrating them by hand. That would allow me to revisit some of my old ratings and adjust them for my changed tastes. As far as I know there's no export function beyond that, however.

I'll give taste.io a spin. It looks like it might be a bit streaming focused. I know letterboxd is where real film fans go, but I'll miss that usually spot on star prediction.