If they wanted to get rid of the Sorceress they should have come up with a better way, instead of killing her, which is a terrible idea.
Maybe they could've done something similiar to the classic where she is sent to another dimension and Teela had to take her place while she was gone. But instead of making the episode a stand alone, it could've turned into a little saga where they are trying to bring the Sorceress back.
That way we would have had the chance to see Teela in the role of the Sorceress but for a limited period of time. If the idea was to show Teela's potential as a Sorceress to me the best idea is the one I stated above.
If they had killed the Sorceress, it would've been an unnecesary death.