Do you know the story of seasons 4 and 5?
For those that don't - Babylon 5 was originally intended to have five seasons. The arc was laid out before a single episode was ever filmed. They made three seasons. During production of the 4th, PTEN, the network Warner Brothers used for the show, shut down. So, it was not clear if the 5th season would happen.
So, J. Michael Straczynski did a lot of slash and burn on season 4, to jam in many elements intended for season 5, to make sure the fans got resolution on some of the core plot elements. Then, after that was completed, they got the order for season 5. This nonsense made scrambled eggs out of how the show was intended to go, and also was also party responsible for the departure of Ivanova.