"Objects in Motion" and "Objects at Rest" aren't fillers, they conclude the arcs for several characters and set up new ones (if the series had continued), like for Talon or Halloran.
"Grey 17 Is Missing" has a filler A-plot, but the B-plot is very important with Delenn becoming Ranger One and Neroon gaining respect for Delenn, the Rangers and Humans, which later on becomes very important for ending the Minbari civil war.
"Grey 17 Is Missing" has a filler A-plot, but the B-plot is very important with Delenn becoming Ranger One and Neroon gaining respect for Delenn, the Rangers and Humans, which later on becomes very important for ending the Minbari civil war.