Not a new reading, just edited, or perhaps a different take was used. The actual line in the episode was, "Your commanding officer, Commander Sinclair, will not be returning to Babylon 5. He's being reassigned. Permanently."A lot of those lines are altered or possibly even rerecorded. "Commander Sinclair is being reassigned," for instance. I don't think that's even the lines from "Points of Departure" reedited, just an entirely new reading.
The main reason it almost certainly couldn't have been a new reading was because the actor had burned his bridges by bowing out of 'Severed Dreams'.
There were at least two versions of the opening. IIRC, JMS wasn't available for the mixing of the first version and went back in to tweak them and ensure that all of the lines were audible. Sadly, I think they used the original one for the DVDs.
Jan