"It seems to me that William Shatner got a lot more work than the rest. Is
there a reason for this that you know of? Would it help the
eventually-to-be-ex-members of the B5 cast?"
Not for some time, and not consistently. That he was the lead helped, but
the actors from that period had a real problem which, fortunately, has
been mitigated a bit in the last 10 years or so. Working in SF isn't as
much a liability anymore, so it shouldn't be a big factor for current
B5/ST actors.
jms