I think we're just in the last year of relying on the old guard, while the new signings become the new core of the team for next year. If we build the core of the team around Stones, Gundogan, De Bruyne, Sterling, Sane/Jesus, Aguero then we only need to fill in the gaps, but they are still bedding in so we are still to reliant on the old core who clearly aren't up to being relied on any more. A couple of young energetic fullbacks, a new holding midfielder who can play the ball and maybe another centerback and we're pretty much there, especially if we start to utilise our academy for the fringe spots.
At the moment we are reminiscent of the team Guardiola took over at Barca, in need of letting the Ronaldinho/Deco/Belletti/Zambrotta's go to let the other players take the reigns.