I think they applied Stilgar's whole arc to the "northern" Fremen concept. They go from skeptics who laugh in Paul's face to being indistinguishable from the southern fanatics by the end. Paul even has a line similar to the one posted above, but applied to the Fremen broadly ("They used to be friends, now they're followers").

I do wish we got to see Stilgar go through more of a transformation himself, but I like Bardem's performance enough to overlook it.