Continuing my series attempting to reconstruct how Babylon 5 was originally (for certain values of original) "supposed to" go. More detailed explanation and Season 1 are here, although note that since writing that original post I have gotten access to JMS' "original" treatment and am no longer working from summaries.
Known: Delenn gets pregnant with Sinclair's child. Garibaldi quits his job as Chief of Security as a result of his drinking, and begins operating as a mercenary out of B5. There is no mention of a Psycorps connection, Lise, Edgars Industries, or Zack Allen.
The Shadows would first be shown onscreen at this point, and the description of them, while vague, is consistent with how they appear in the series. They would initially present themselves as fighting to free the other races from the Vorlons, but in truth they desire to rule.
Speculation: Between the lack of a rebellion against Earth and the general slower pace of the treatment as opposed to the series, very little seems to happen this season. Perhaps G'Kar and the Narn resistance would have gotten focus episodes, or some variant on the Centauri Cartagia/rise of Londo plot might have occurred. Another possibility, given events in the treatment's version of Season 5, is that the Minbari Civil War might have started, but not been resolved, during this season.
At this point it should be clear that the series as aired had gone completely off the original rails in Seasons 3 and 4. The Shadow War was resolved in early Season 4 in the series, yet is still a proxy war at the END of Season 4 in the treatment. Babylon 5 is still part of the Earth Alliance, Garibaldi never leaves the station, the entire Mars plot and associated cast is nowhere to be found, and Clark is still in charge with no resistance from Sinclair and company, despite manipulating his way into power via assassination just as in the series.
The Shadows as rebels against Vorlon manipulation is an interesting
concept. It leaves open the question of whether the Shadows are one of
the younger races manipulated by the Vorlons who have advanced far
enough to turn against them, another race of equivalent age and power
who just never bothered to get involved before, or, perhaps most
interestingly, renegade Vorlons. This would cast an interesting light on
the "angelic" presentation of the Vorlons, making the Shadows "fallen
angels." It also seems likely that something similar to the "meeting"
scene from "Z'ha'dum" would have happened in this version of the show,
where someone would explain to Sinclair the Shadows' rationale for their
actions. Perhaps Catherine/Caroline would have had that duty.
Regardless, it seems that both the treatment and show versions give the
Shadows a reasonable-sounding rationale, but belie that rationale
through the destructive and manipulative behavior the Shadows have
exhibited to this point. In the original plan, it seems likely that there would be a good deal of dramatic irony regarding this point, as the implication in the treatment is that the audience knows how the Shadows are manipulating Londo more or less from the start, but the human characters don't find out until the season 4/season 5 bridge.
Continued in two weeks...