Babylon 5 was a whole new ballpark when it came out in the early 90's. Good television is now everywhere, but when B5 came out, it was completely unconventional to have a continuous plot over five seasons. At the time "one plot per episode" was the accepted standard, and while the dramatic arcs of for example Star Trek, the Next Generation (ST:TNG) eventually became longer as the script writers got more confident, the arcs of B5 were supposed to last through the seasons from the beginning.

The writing is occassionally weak, and thus it pales in comparison to more younger fantasy productions like Battlestar Galactica reboot, or Game of Thrones. But at it's time it was groundbreaking.

The moments of epic were really good since they were preplanned and they could be foreshadowed much in advance. Hence moments like (spoiler alert...)

... Earth falling into totalitarian state, bombing of one of the alien homeworld, the Shadows overwhelming Centauri prime, etc, were nearly unheard of narrative high points due to the buildup to them over the series.

There were lot of not-so-high quality filler episodes and so on, which make the series more of a cult classic rather than ... an obvious classic.

And yes, I categorized space opera as fantasy :)

I can't say I agree with the characterization of B5 as "paling in comparison" vs BSG at all. I've went out to watch B5 rather late, after I've already seen all of these other allegedly superior shows, and I still found it to be one of the strongest if not the strongest sci-fi offerings.

Seconding. BSG (the 2000s one) was top #1 of sci-fi series for me, but after watching B5 recently, I believe the latter has better writing overall. I really wish someone would do a remaster of that series.

As someone rewatching it now, I'm surprised by how few pure filler episodes there are.

At minimum, every episode at least advances a core character. And usually has one Easter egg related to the overall plot.

As you said, compared to TNG, early DS9, or X-Files, this was groundbreaking stuff on broadcast TV.

As fsloth says below, JMS knew every plot point from day 1 and had trap doors for every character. If an actor's contract fell through after 2 seasons, they didn't have some emergency, they enacted the back up plan (Talia being replaced with Lyta). The shows lead had mental health issues and was also replaced after season 1 with some later cameos. It seemed like it was obviously meant that way. Even the super fans didn't know until recently when the actor died.

Yes B5 had some painful filler episodes and the acting was both amazing (G'Kar, Londo, Delenn) and at times bad, but overall the show is the one show that has stayed with me since Kindergarten. Just like TNG episodes (the drumhead and measure of a man) served as mini courses in morals, ethics, and philosophy for kids, Babylon 5 was the same, but more memorable to me as the arc was 5 seasons, two spinoffs, and like 5 TV movies. I learned all about politics, facism, standing up for what's right, leadership, really cool spaceships, the impact of discrimination, and diplomacy (kind of :)). A great show to watch at an impressionable age.