Well, at least prosody allows you to add a whitelist of servers for which strict verification of SSL is not enforced (and comes with gmail.com as the example content), so it is possibile to talk with people on gtalk without having to allow substandard settings with everybody else.

It's definitely not something that I'd like to depend on, however, just something that currently makes it somewhat easy to have a migration plan to something else that doesn't require to be all-or-nothing-now.