The Vorlon / Shadow resolution came maybe a little too quickly. But really, it's not like the younger races could have actually fought them. Once their true nature was revealed thing proceeded to their logical conclusion. The Earth cival war however was given a more climatic ending. In fact I think JMS when forced to tighten up season 4 to wrap up as much as possible (with season 5 unlikely) he did so more at the cost of the Vorlon/Shadow showdown then the Earth civil war resolution.
And it's worth pointing out that this show was most certainly not written by committee. Starting around the middle of season 2 JMS wrote every single episode except a couple of episodes in season 5. One vision.
As for the 'Sheridan cult' that some have a problem with here... I don't really see it. Sheridan became the leader of the resistance. It's the type of job that will get put on a pedistal. But even then there were some that didn't buy into it, people who actively opposed him. And there were several other ongoing threads at the same time (most especially about Centauri and Narn) that Sheridan was not intimately connected to. So the show never become about Sheridan as such. And the season 4 finale did a nice job of looking at his character from a different perspective.