Wouldn’t be great to able P2P file sending on Kontalk clients?
I mean, to have the possibility of send big/large files using P2P connections. Just for big files! 
Like an illustrative example:
A) From 1 byte, to 15 Mb, using servers.
B) From 15 Mb to 50 Mb (or more) a P2P connection.
Also using LAN connections, if are available?
From here you can go for more customized options. Like configurable quotas, and so on. But, just take the initial concept.
That is my collaborative job, a suggested idea. Sorry 