Of course not. You could've watched all of those shows way before Toonami came back.
Ghost in the Shell has been running on and off for years now and you can watch the whole thing for free on Hulu. Samurai Jack was airing on Boomerang at an earlier time for years now before moving to Toonami. FMA is free on Hulu, too. Brotherhood has been airing for a while now and Inuyasha has been there for years as well.
It's filler. The shows are good (except for Inuyasha), but still filler. I'd watch if they were on earlier.