Also...for all the talk of "John C. Horfenbottom planned out the series from the beginning!"...does that really matter when a) half the cast left after the pilot and b) the captain left after the first season?
It's fine to not like B5. It's very much a product of the 90's network syndication era, and has aged poorly in many ways. The acting was often soap-opera quality, and DS9 had a much higher production budget. I personally think DS9 has aged far better, despite my love of B5.
But the cast turnover isn't a significant reason for that. A grand total of three B5 characters from the pilot didn't make it to season one (the doctor, the telepath, and the first first officer), and one of them (the telepath) returned to become a pivotal character for latter seasons. And yeah, the actor playing the Captain tuned out to be a raging schizophrenic half-way through filming the first season, but you should have seen the dumpy French faggot Roddenberry really wanted to play Picard in TNG pre-production. Also note that all but one of the season two cast went the rest of the series, and on to the shitty cable telemovies.
The pilot is far more objectionable for Delenn's low voice and masculine makeup, which was a hangover from JMS' original tranny alien concept for Delenn that didn't even make it to the pilot, and was completely scrubbed from season one. He was a tranny chaser long before Sense8, you see.
Ignoring that, the thing people like about B5 is that, unlike DS9 or almost any contemporary show, it
did have a story arc planned from day one. At that point, TV was purely episodic. No real changes could happen to the characters from the start to end of an episode. Each story had to be interchangeable. DS9 eventually got to multi-episode arcs in later seasons, but B5 was there from the pilot. Sure, the larger story had to change due to production challenges, but
there was a larger story there.