Oh that sounds exciting, would it also solve the current performance issues when moving large amounts of data? It's currently the only reason I still have to use public IPs for some applications.
Does the current setup with magicsock mean that tailssh behaves similar to MoSH (in dealing with resuming a session, specifically)?
Yes.
But so does regular SSH over Tailscale, so Tailscale SSH isn't special in that regard.