Is there any chance that you will provide us with an option or a tool to rebuild thumbnails for attachments? Maybe there are any script which can make that. I have same problem like Cujo, after migration a large part of thumbnails looks awful.
No, I've been super busy. It's on my todo list but I'm not sure when I'll get to it. To be honest I think I want to rewrite parts of it if I'm going to release it, as it comes with a few caveats and was written specifically for my use case.