I really hope arcs from now won't last more 60-70 chapters and focus on a smaller cast.
And yes that includes the final war. Final war will be a saga but it doesn't need to be a 250 chapters long arc , it could last several weeks or even months and happen on several islands. Kinda like Alabasta was subdivised subvidided between Whiskey Peak, Little Garden, Drum and Alabasta itself
But who am I fooling, Oda thinks the longer the time the straw hat spend on a single location, the better. And the more the merrier