Is calling Girl Meets World a "spin-off" more appropriate since there was a change in focus from Cory in the first series to Riley in the second? Is is not really a continuation of the original story, but a telling of a different one with some elements from the first being used? In other words, even the stories that do focus on Cory and/or Topanga generally tend to revolve around Riley, or they're just very minor B-stories that take up little substance in the episode.

I think GMW was the spinoff, not a sequel.