@didek
If they use the same protocol, you end up with both lowest common denominator security and making it largely impossible to add features — and that's assuming interop even works. Client side bridging requires that every client implement every protocol, yielding the superset of vulnerabilities — and that's before we start dealing with how you present so many different sets of features in the UI in usable ways. Then we get to talk about how anti-spam is going to work in an ecosystem like this, not to mention impersonation, etc.
@IzzyOnDroid @cstross