As the co-chair of the FTP Working Group & author of 3 RFCs, I can sympathize.

Coming from open source (Metalink) & working on Internet standards can be a very frustrating thing.

I pushed for improvements but made no progress.

be sure to check out the new FTP Working Group at the IETF if you're involved in FTP implementations.

we're working on new and old extensions like a HASH and RANGe command, and HOST.

just join up on the mailing list!

http://tools.ietf.org/wg/ftpext2/
https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fwww.ietf.org%2Fmailman%2Flistinfo%2Fftpext

check out metalink. most linux distributions use it for large downloads and software updates.

it would be cool if they could use metalink, an internet standard for describing files offered in hybrid ftp/http/p2p content distribution systems, already used by a lot of open source projects.

You can use Metalinks for downloads without errors. It can use whole file checksums, or partial file checksums to repair errors.

try a metalink download from Fedora using aria2. it can use torrents but also mirrors.