They don't need a complete rebuild but they do need quite a lot of players if they want to be doing well in the league and champs league every year. Maybe 5 or 6.
I suspect we'll see another whopping great sponsorship deal heading their way shortly so they can continue to dodge ffp (or take the 30 pence fine again), and they'll go on a spending spree again. Them and PSG seem to be taking no notice at all about ffp and know they can just bypass it with new 'sponsorship'.
They've only really got Aguero, Silva and maybe an on-form Kompany that are irreplaceable, everyone can be replaced for better.
Also as mentioned above, they're about to run into british players problems, not sure who they'll go after, but maybe players like Walcott would make sense. And then whack him on the bench of course. Massive offer for Kane maybe?