It is very easy to change commishes. Too easy actually. I took over as commish of a world with a single email. And, I had the commish taken from me--I had no issue with it without a confirmation email.
I'd assume if I complained or the other commish complained they would have changed it back. I took over to prevent a world from going public when we werent sure if the ex-commish would be on in time.
If a commish is not acting in the best interest and the league takes note, the situation drarcher mentions could have been reversed easily. Make the commish change, and invite the old owner back in. There would probably be a power struggle, but if the facts stated were true, Im sure it would be worked out.