Nick, rather than have a set of commands to repeat, perhaps we create a blacklist of commands that should never repeat.
Either way, this is a whitelist of ones that I could see some use case to repeat. Some are obviously more important than others but I tried to imagine a reason to not let some of them repeat while considering scripting reasons why someone may want some of these to repeat (like cat or ls for example redirecting output to a file to keep a list of files somewhere up to date).
cat Concatenates any files and sends them to stdout.
check Checks the files in the source and destination match.
cleanup Clean up the remote if possible
config Enter an interactive configuration session.
copy Copy files from source to dest, skipping already copied
copyto Copy files from source to dest, skipping already copied
delete Remove the contents of path.
genautocomplete Output bash completion script for rclone.
ls List all the objects in the the path with size and path.
lsd List all directories/containers/buckets in the the path.
lsl List all the objects path with modification time, size and path.
md5sum Produces an md5sum file for all the objects in the path.
mkdir Make the path if it doesn't already exist.
move Move files from source to dest.
moveto Move file or directory from source to dest.
purge Remove the path and all of its contents.
rmdir Remove the path if empty.
rmdirs Remove any empty directoryies under the path.
sha1sum Produces an sha1sum file for all the objects in the path.
size Prints the total size and number of objects in remote:path.
sync Make source and dest identical, modifying destination only.
authorize Remote authorization.
mount Mount the remote as a mountpoint.
version Show the version number.
gendocs Output markdown docs for rclone to the directory supplied.
dedupe Interactively find duplicate files delete/rename them.
listremotes List all the remotes in the config file.
Most important whitelist: copy, copyto, move, moveto, sync, rmdirs
Also, i'd do away with having two parameters and simply have a --run-interval and make a zero (default) be the OFF setting. Anything above zero could enable it for that duration. Less switches.