User blog comment:Hidden Scorpius XI/My impressions on "No Safe Haven" (V4-E12)/@comment-28831435-20170208175019/@comment-4010415-20170208202411

If volume 4 was filler, then literally nothing would've progressed... Instead


 * We got Ren and Nora backstory


 * RNJR made it to Mistral


 * Yang became emotionally able to put the prosthetic arm on and leave home


 * Weiss lost her status as heiress and escaped her family home


 * Ironwood decided to close Atlas' borders after having started a Dust embargo


 * Cinder made a recovery


 * Blake learned her lesson and finally decided to stop running


 * Blake decided to take control of the White Fang back

If RWBY completely skipped volume 4, everyone would wonder "What the fuck happened? I thought Weiss got taken home. Wait, she's not heiress anymore?! Since when?!! When did Yang get a prosthetic arm and get over her depression? In the volume 3 finale, Blake was in Vale, so why is she suddenly in Menagerie? Why is Sun there? Why does Blake suddenly wanna take over the White Fang? Is she done running? Whoa, Cinder looks messed up, but I guess they skipped her recovery?"

So, no, volume 4 was not filler. It's a build-up season, much like volume 2 was, yes.