To be fair, the rushed pacing wasn't the fault of the script per se. They basically got told that they would get a fifth season, so they tried to cram the Shadow/Vorlon war and freeing Earth into one season, when the initial idea was for the return to Earth to be season 5.
Only after shooting most of it, and shooting the final episode (Sleeping in Light), did they get told they did have a 5th season, and then basically stretched out a few loose threads. They wrote and shot a new "end of season 4 episode", wrote up that whole "first year of the alliance" with the threads they had for season 5, and then put Sleeping in Light on the end there.