Whether it would have eventually had a more focused story arc is impossible to say at this point.
It's a Joss Whedon show. I think we can infer from his previous efforts what the pattern would have been. Season 1 would have been establishing premise and characters; then a clear-cut arc (probably the Miranda stuff) would have taken shape in season 2, and thereafter each season would have its own arc with a slightly different focus.
Oh, and season 7 would have just ended last spring.....