I can tell you exactly why Jar Jar was the 'key' to the saga. Without him, Palpatine wouldn't have been given the power to create the clone army. This led to Palpatine being given more power until he was Emperor in all but name. Then in name. The main issue is that in neither the original trilogy nor the sequel trilogy is Jar Jar ever mentioned. In reality, Jar Jar wasn't even an idea at the time of the original trilogy.

Sorry, but the Barney and Robin divorce was written in the stars season back when they dated. The reasons they originally broke up was still there. They talk of Barney entertaining himself while traveling with Robin for work. The problem was the best way Barney had to entertain himself was picking up women, which is frowned upon when you're married.

The issue with Rory is in the early seasons she was from humble beginnings. She was raise by a single working mother and a town that loved her. The first episode changed that, she received help to go to private school. From that moment on she started to develop her an up-class mentality. Logan was the only one to call her out on it, that she isn't the humble blue collar girl attending Yale, that she saw herself as.