I brought this up in a post about Git bundling, but am now looking for a more generic solution. I have some directories that rather than upload a bunch of small files which might be subject to certain cloud limits (e.g. Maildir) it would be awesome if rclone had a flag that can create an archive during sync/copy based on a filter. I believe this could greatly increase transfer speeds for certain scenarios as well. My Maildir for example has over 30k files in it, which of course is going to be a lot slower to sync than a single archive and providers line OneDrive have limits on the number of files you can have. Several archive formats can be streamed as well to avoid have to create a complete cache before uploading/downloading.
Google has some rudimentary support for previewing ZIP/TAR files as well, so they may actually support a way to remotely update archives—but probably not, especially for an encrypted remote. For now, it would just be nice to have a way to archive/extract files with flags using a filter and some naming scheme that makes sense (sort of how rclonelink) files work. In the future, maybe a way to set thresholds and create archives to append (create appendable archives with more archives) or clean (rearchive back into a single file archive).