One red flag from that podcast:

When asked how they might deal with abuse of the service to distribute illegal files, he suggested that you could compare uploaded files to hashes of known files. This doesn’t make sense in a system where the server has no knowledge of the unencrypted file, since the same file encrypted with two different passwords will result in two different hashes.

I don’t know know if you guys are aware, but a user named timvisee on Github forked Mozilla Send and brought back the service. He even hosts an instance himself, and provides the instructions on how to set it up yourself. Would be cool to see Mozilla bring it back offically in some form though.