<GASP>
Yeah, Babylon 5 was one of the earliest players in shows that broke the old syndication rule of making sure every show ended with everything being essentially the same (great for doing re-runs) in favor of making real story arcs that change how the show progresses. There were issues with actors wanting/needing to quit their roles over the 5 years of filming, but they were able to write their way out of them satisfactorily.
The idea wasn't totally new (soap operas had been doing it continuously for decades before B5) but it sure was new for most shows. It also pioneered CGI. Obviously, those parts could look far better 30 years later, but it's still good enough to get invested in the story.
It delves deeply into nationalism (planetism?), factions getting locked into a cycle of revenge, authoritarianism, and the role of the military when loyalties get tricky. It's got some good humor sprinkled around, too. And, being 30 years old, it's cheap!