Gaffer Tape said:
You're the most well-known single movie fan around here, so you do tend to be used as a case study.

Cool... I always wanted to be a case study....I think. ;-)

Gaffer Tape said:
How was Ben's death the necessary choice for the mission to succeed?....How did his death keep the droids from being captured?

I think it served two purposes. He would still be able to help Luke by speaking to him through the force - and - it provided a momentary diversion so that the group could get on board the Falcon, have a chance to escape the Death Star (thanks to Ben's tractor beam help), and deliver the technical readouts.

There were certainly other ways the events at that critical moment in the story could have been handled, but I think it worked well. It also forced Luke to grow up even faster - not that he needed to after seeing his family slaughtered. However, with Ben & his only family gone, he had to reach deep inside and make some very adult decisions. After Ben was killed, he was truly on his own. He was in the thick of things in a way he hadn't even dreamed of when we first meet him.