I think they made the right choice when they killed Gan - the character was going nowhere. If I have to choose another character, it would be Jenna, even though I don't like losing a female cast member, for the same reasons - the character isn't essential to the dynamics of the show. You could do B7 quite well with Blake, Avon, Vila, Cally, Orac and Zen. (And Servalan and Travis.)

In hindsight, it may have been better to kill Jenna. That would then allow Gan to take up the Doubting Cally dialogue in Star One, and indeed that episode may have been even better with Gan and Cally at opposite extremes,with Cally being all gung-ho. The only downside is that we would lose all those fantastic Jenna arse shots in "Voice From The Past".