Recoil, I'm gonna have to disagree with you. Season 5 could have been so much better with Ivanova.
I don't mind how season 4 was compressed. Sure, it would have been great to have the season end with Intersections in Real Time as the cliffhanger, as was JMS' original intent, but the way it was handled was good, too. I also don't hate Byron as much as others. Yes, the idea of having Byron earlier but as a smaller presence to space out the telepath thing would have been great, but there it is.
The one major thing I regret being lost for season 5 is Ivanova. Heck, I don't even like her (and I think Claudia Christian's acting is the worst of the major characters), but the setup for her possible role in season 5 was perfect. Her own issues with telepaths and their persecution, as well as the loss and regret over Marcus, would make her ripe for the Byron story-arc. As commander of B5 taking up the cause of the telepaths, she would find herself in direct conflict between her two greatest battles: telepaths and B5/Sheridan. She'd be stuck in the middle until Byron dies. Then, she would realise how he used her (albeit subconsciously, perhaps) and that her struggle with her real friends were for nothing, and all because she was hiding from herself the real reason she hooked up with Byron in the first place: Marcus. End result: the bitter, despondent General Ivanova we see in Sleeping in Light.
Now, you tell me if that wouldn't make for some amazing television.
When I first read about what could/would have happened with that, I was stunned. It is the perfect way to end the series. And it didn't happen.
Oh sure, they did a fine job making up for it, but the loss of the central character to season 5 was a vicious blow to the show. With her in it, season 5 could have been the best of the show, despite the other changes with the story arc spacing.
Although it would be made fun of a lot, perhaps it would have been better to use a different actress to portray the Ivanova character. Sure, it would be weird (especially with Sleeping in Light airing after it), but at least the great story would have been kept.
I know there is a huge "I love Lyta" contingency at this board, but let's be real- her character simply did not have the development and depth that Ivanova did, simply because she wasn't on the show as long, nor was she a major character. The significance of her hooking up with Byron isn't as powerful as if Ivanova would have done it, given the whole Marcus thing.
Did they do a good job with season 5 given the difficulties they faced, including the loss of the central character? Yes. Unfortunately, it never had a chance to compare with seasons that preceeded it.
That being said, there's a lot to like in season 5, especially Londo. It's just missing that "umph" that 3 & 4 had.