I just finished a refactor of the Jingle File Transfer code in #Conversations_im. 
The P2P file transfer code was probably one of the oldest code in Conversations.
The new code should be a lot more resilient and brings support for XEP-0343: Signaling WebRTC datachannels in Jingle¹. This means we should be able to exchange files directly with #XMPP web clients.
Due to the better NAT hole punching of WebRTC vs Socks Bytestreams we now have a higher chance of actual P2P.

¹: https://xmpp.org/extensions/xep-0343.html