Yeah, I agree with the above. It wasn't crucial to the movie and it would have been a slight distraction from the events that the movie was really about - possibly even confusing people who were not familar with the Soul Hunters. Also, if you think of it as the fact that Emperor Londo is telling the story - and he really had only a little time to tell it in and he was probably quite drunk (to make his Keeper a sleeper) - he wouldn't have included unnessary details like that.
In the episode when Delenn goes into the Dreaming (that what it's called?) and remembers her time as Dukhat's chosen and joining the Council, when they see the Earthforce ships, they also see a few Soul Hunter ships. They realize that this means death - and death of someone important - is only moments away ... but they are helpless to stop it in time. Leads to question if they could ... if the Soul Hunters were already drawn there, was there any way to stop the death? If Dukhat was not to die, why would the Hunters have come? Never seen any evidence that a Hunter is draw to possibly death - always actually death (or what seems like it).
The book was probably trying to tie in with the first Soul Hunter episode where we learn Delenn (and others) stopped the Hunter from taking Dukhat's soul and thus fell into degrace with his kind and later into madness and explains his anger against Delenn.
