In addition to SFTP, you could maybe add simple FTP (even if unsecure it could allow to use quick free hosting as staging account) and FTPES (sometimes, you have accounts without SSH, so SFTP is impossible).
Thank you for the suggestion! FTP and FTPS are not widely used these days, but if there is sufficient interest we may integrate them.
For FTP, I understand (even if most of the free Web accounts stick to it; pushing for upgrades, of course), but FTPES is quite useful because of the fact it supports the ASCII mode (while SFTP is always in binary). It doesn’t seem to be important about BSS since I saw you force a LF end-of-line in every file, but when you manage websites between different editors under Windows, Mac and Linux and you’re not always sure about EOL, it’s useful to be able to auto-switch to ASCII mode depending on file extension (even if only to save a few bytes replacing any CRLF by LF).
FTP over SSL would be very nice.