Also, she and John couldn't get together without it
For the last time: NO!!! Sakai would never have had the role of Anna Sheridan because of one tiny detail: the Shadows had already been awoken in Season 1. And there would be no blowing up Z'ha'dum, no Lorien, no ISA, etc.It would have been interesting to see just where things would have led had Michael O'Hare stayed with the show. Would it have been Catherine Sakai mysteriously returning from Z'Ha'Dum at the end of season three, not Anna Sheridan?