Major Legislation passed by LBJ: Civil Rights Act, Voting Rights Act, & the legislation tied to the Great Society
So yeah. IF you think the Civil Rights & Voting rights were among the most important pieces of legislation ever passed, then LBJ blows Kennedy (and many other presidents) out of the water.
Half the posts about this story have been "duh, we all know this". But yet, it doesn't change. His taking a bullet would have only cost him his job an enacted no change. Look at Snowden. He squealed on the NSA and about all that has changed is that he can't live in the US anymore.
If you were limited to 1 term, then their would be nothing holding you to the people who elected you. Those elected would end up serving their own self interests - more blatantly then they do now - instead of the people.
Plus, to get ANYTHING done in Washington you ahve to know how to get it done. Rookies don't accomplish much because they don't know how it works. That's why Pres. Kennedy was a failure at passing legislation. He didn't know the ropes of Congress. IT's also why LBJ actually passed all of the legislation that Kennedy dreamed of passing. LBJ spent a lifetime in Congress and knew how the system worked.
*The question is what percent of any voters are informed.