So you get a prequel movie featuring a whole bunch of new characters we don't know, don't care about and are doomed never to even be mentioned in the show (since you have already made 4 seasons of it without mentioning them). Reducing all of the series' characters to the level of Sinclair's cameo would (for me) render the whole project redundant, not to mention how disjointed it would get by repeatedly cutting back from the main narrative (which doesn't now feature Sheridan and the others) to show the incidents already established as having taken place during the Minbari War ... Sheridan taking out the Black Star, Ivanova losing her Brother, Franklin refusing to hand over his notes etc.
I agree it is a stretch, but I don't really think it could have been done any other way.
Well I think for the MOST part, they did things right. First off, part of the reason for the movie was to SEE what our heroes from the series did in the Earth-Minbari War. We heard about it, but this is putting all the pieces together in one tale.
* Sheridan taking out the Blackstar
* Franklin refusing to hand over his notes
* Delenn's role in the Grey Council
* Sinclair in the Battle of the Line
* GKar selling Weapons with the Narn
* Invanova losing her brother
All those were mentioned in the series. Where they sort of stretched things a bit, was with the added parts that those characters ALSO ended up doing.
Mainly, Franklin and Sheridan being there at the attempted "peace offering" meeting that the Centauri foiled. That to me was an unnecessary stretch. They could have had ANY two Earth people meet GKar (who was a series regular) and Lenon (who was a main character in this movie) and it would have been fine. But for Sheridan and Franklin to also be the ones to go seemed to much for them to do in the War. Couple that with the fact that Franklin doesn't seem to have met Sheridan when he arrived at B5, yet he served with him in a crucial part of the War, and was brought to a Minbari Cruiser with him. Yea, I think after all that, you remember a guy. In fact, they both would have probably remembered GKar.
They should have just let that part be done by someone else.
I do think the additions that Londo did in the War were good, and very believable.