Red Hat issues a "kill -9" to sshd when the sshd is shut down, while Debian issues a SIGTERM. The difference in behavior is that the Red Hat Linux sshd leaves all clients in a "stuck" state (only kill -9 able) while the Debian sshd nicely disconnects and the clients return cleanly. This should not be hard to fix and will spare me a lot of annoyance.
It should only do a kill -9 if it doesn't respond to a kill -TERM, looking at the init script.
This has been my experience with recent initscripts versions as well. The first "service sshd stop" kills the master listener, and a subsequent stop attempt will only use kill -9 if a kill -TERM doesn't cause the sessions to stop. Have just checked with the current tree, and the clients receive a "Connection to host closed by remote host." message. Please reopen if you're seeing this problem with the latest versions of initscripts and openssh-server.