It was innovative. It was epic. It had a huge effect on Sci-Fi television (which was largely Star Trek:TNG and nothing else at the time).
But it was cheesy and uneven. Yes, seasons 3 and 4 were some of the best sci-fi ever made (at the time, at least). But season 1 was mediocre at best and has aged pretty badly. Increased production values for new TV also makes a lot of Babylon 5 difficult to watch, now.
The Wikipedia article goes into this. They wanted to film widescreen but certain necessary equipment wasn't provided so they filmed in 4:3 but with the idea that you could crop it to 16:9 later. Also most of the SFX were done in 4:3 but could be cropped.
The widescreen conversion thing was executive short sightedness at it's finest!!! We offered to do ALL of Babylon 5 in widescreen mode if Warner Bros would buy us a reference monitor so we could check our output. (only $5000 at the time) Ken Parkes (the "Business affairs" guy) and Netter (penny wise, but pound foolish) said no! So we did everything so it could be CROPPED to be widescreen! Each blamed the other by the way. Doug Netter said, "Ken Parkes said no". Ken Parkes said, "Doug Netter said no". SHEESH!!! So for $75 an episode they could have had AWESOME near Hi-Def.
But it was cheesy and uneven. Yes, seasons 3 and 4 were some of the best sci-fi ever made (at the time, at least). But season 1 was mediocre at best and has aged pretty badly. Increased production values for new TV also makes a lot of Babylon 5 difficult to watch, now.