Probably magical is the correct word to use. It was unusual for the time because it used a story-arc format that has become rather common these days. JMS wrote a 5 year story which is ongoing through the entire series so it's not something you can dip in and out of like Star Trek. Unfortunately the WB messed with it almost constantly up to the point where they informed JMS the show was being cancelled after it's fourth season. They then changed their minds and commissioned a fifth and final series. The effect of this was JMS tried to tie up the story in season 4 then had to pad out season 5. Thats why I say it's the official ending I linked but there is in fact another ending in season 4.
It's still a fantastic show though. There has never been anything quite like it since.

Besides 2 very good characters (G'Kar and Londo Mollari) the show wasn't bad but just ok to my taste.