Yeah, I sent a ticket yesterday. Apparently a commissioner can never leave a world unless there are no more teams in the world. This was the response from Admin:
"The commissioner of a world cannot leave a world unless there is no one else in it. To move, you're going to have to have us switch the role of commish to another user, back out and re-join, and then have us switch the role of commish back to you. If you would like to proceed, we need to know who to make commish temporarily."
Seemed more trouble than it was worth, so I am staying put.