Lisa Bonet should be listed twice. The Cosby Show benefited from her departure as well.

She was even worse as a Romulan. What a contrived soap-opera plot and character that was.

Yes, MASH, thank you.

MASH is criminally absent from this list. It is the classic and best example of a show that improved with the loss of key actors. The show got significantly better with each of three major cast member departures: McLean Stevenson (Henry Blake), Wayne Rogers (Trapper John), and Larry Linville (Frank Burns). It easily…