If you're referring to the scene between Kosh and Sinclair in "The Gathering", (Kosh's greeting) that wasn't in the original airing. It was inserted by JMS after the series ended. And I myself think Season 1 was the best of all. It set the stage of everything that came later.
I don't think it should have been inserted. One of the things I like about Season 1 (And don't get me wrong, I do enjoy the season but it's not as good as Seasons 2-4) is the mystery surrounding Sinclair and why the Minbari surrendered. To insert that line takes a little bit away from that mystery in episodes like And the Sky Full of Stars, doesn't it. Of course having known the series already, it's not much of a spoiler, but I'm just not sure it was wise to reveal everything right up front like that.