As much as I hate to say it, I don't think JMS had his heart and soul in Crusade in the same way he did with B5. It clearly had potential but it wasn't his very reason for breathing. He was writing the arc for B5 for years, maybe even decades, before filming. I was SO surprised that Crusade ever went into filming at all. He had been so adament that 5 years was IT, period, full stop, end of story that Crusade felt like a favor he'd done for the fans as opposed to something he had to write. It always had potential and I would have thoroughly enjoyed it, but it would never have been the same. He was, after all, famous for loving the dangling plot line. There was something powerful about unresolved endings.
That said, I wonder what JMS is up to these days. Probably trolling around the internet as usual. It's been a long time; I hope we hear from him again soon.