A 20MB limitation is a serious limitation! While we used external systems for backups, since WHMCS offers backups, it should be functional.
As far as complaining about things, FTP on it's own is not secure, and at this stage in the game, nobody should be using raw FTP. If you are offering FTP to users, you need to take a look at your security.
For me, sFTP is a requirement. But then I'm more paranoid about security than others might be.