When a message is marked as sticky, the next time an admin looks at it, instead of having the sticky icon it should have a de-sticky or an un-sticky icon. That way you eliminate the need of clicking back. Takes away an extra step that if initiated would be unnessessary.
One button/link controls both locking and unlocking. Where's the extra step?
the button doesn't change from sticky to unsticky.
The default theme in SMF 1.1 takes care of this.