Yeah. I remember him telling Sheridan that their alliance that was started near the end of season 2 would be the first of many and then you never see the guy again.
I have seen that episode lots of times, and I have always got the impression that Draal was referring to this being the first of many alliances that Sheridan would have to make before the situation was resolved. And Sheridan did indeed make many alliances with other races in order to fight the Shadows - leading to the formation of the Interstellar
Alliance.
I never ever felt that Draal was saying that this was the first of many times that they would work together.
Besides, the problem with Draal was actor (not story) related. After Louis Turenne played the part in
A Voice in the Wilderness, he suffered a stroke and was unable to take up the role again in
The Long Twilight Struggle, so John Schuck was cast as the younger, re-invigorated Draal, appearing again in
Voices of Authority.
However, when the time came to film
War Without End, John Schuck had been cast in a long running production of (I think) Hello Dolly on Broadway and couldn't get away, so rather than re-cast again JMS just referred to him in the script rather than go down to the planet as originally planned.
IIRC, Draal didn't appear any more after that.
JMS has always had an aversion to characters running around his stories with too much power (hence the Excalibur's power drain when firing its main weapons), so I would imagine Draal was always intended to disappear from sight once the Shadow War was over anyway.