I would love if my VCS tool could also keep track of things like "This diff is the result of running sed -i s/this/that/g .py". I usually split out such mechanical changes anyway into a separate commit, but it would be clearer for reviewers to see that (most review tools show you the overall diff of the entire branch you want to merge by default, making you click further to see patch-by-patch changes), and it would also be easier for me* if the VCS could re-run the sed command when I rebased.
(An obvious next step is Coccinelle-style semantic patches, but let's start with sed!)
(An obvious next step is Coccinelle-style semantic patches, but let's start with sed!)