Better file formats cannot, by themselves, improve an inferior SCM tool that, for instance, processes files with the wrong text encoding or forgets deleted and

Better file formats cannot, by themselves, improve an inferior SCM tool that, for instance, processes files with the wrong text encoding or forgets deleted and renamed files: they would only have helped you for the purpose of developing your code review tool. Standards are meant for interchange, like (as mentioned in other comments) producing a patch file by any means and having someone else apply it regardless of what they use for version control.