Now to target Worf, a very developed and focused on character.....thanks to Denise Crosby. My theory is that if Crosby who played Security Chief and Chief Tactical Officer Yar din't leave the show, Worf would be like Geordi, underused and not developed.
Evidence supports my theory. Look in season 1 before episode 23,
Where is Worf ? He is in a red unifourm as a relief con officer, and will float around from station to station, holding the rank of Lieutenant Junior grade.
After Yar's death....
GOLD UNIFORM promotion to full Lieutenant in the Ops division serving as Chief of Security and Chioef tactical officer.
In episodes late ron like
yesterdays enterprise when Yar is alive.. where is Worf ? I dont know, i can't remeber him being in that episodes and if he was. he proably was in a red uniform somewhere.
So back top the point i attempted to make.. Worf wouldn't be a a fan favorite or as important in TNG if Crosby did not leave so I think She is to reson for his sucess as a character. After 7 years on TNG where did Worf go... to do a few years on DS9