Re: [Sci-Fi] B5: Another has passed beyond the rim...
There are many rumours about it. Some say that because he was more of a stage actor, he didn't like the TV acting schedule. Some say that JMS had originally wanted to do too much with that character and O'Hare's wanting to leave helped. There was even a rumour that he was being creepy around the women. I tend to believe that he wanted to leave for his own reasons and not that he was mad or anything (he did show up in later episodes/movies), and this allowed JMS to bring in Sheridan to lead while Sinclair could become Valen. -- Cry "Havoc!" and let slip the dogs of war
I thought the reason was JMS wasn't exactly satisfied with O'Hare's portrayal, or maybe not satisfied with Sinclair's development, or something like that. Either way I really liked O'Hare and I always wonder how B5 would have been if he stayed on and they played out the story arc with Sinclair at the helm.
The way they retconned the season one finale was kind of weak.
O'Hare will be sorely missed. I always enjoyed seeing him when I catch him on a guest role on some TV series.