Definitely want to see De Bruyne here next year. If we have ambitions for the title and the CL, we need a match winning striker as well; someone who can carry us on our many bad days. Not to mention we'll be needing a top manager.
If we're content with coming somewhere between 2nd-4th then just bring back De Bruyne, Essien and Lukaku. IF we truly want to go for the title, we need to look at the really top strikers. Falcao and Cavani are both ridiculously expensive . Rumours of Tevez and Dzeko both being on the way out from City, but I'm not sure I'd want either, albeit for altogether different reasons. Certainly not an easy decision. Even Falcao is a gamble because he's coming from a very different style of football both at Porto and Atletico, and we all know that we are cursed with strikers failing to adapt. Maybe for our style Cavani would be better, but again, dat price tag. Gomez might be an option as he seems to no longer be 1st choice, he does score a lot of goals (mostly against poor teams) but his game is extremely limited. Jovetic is not a lone striker, but maybe he could adapt. Who knows what we'll do there, but we need to do something if we want to go for 1st.
In terms of a CM, that's extremely difficult because none of the amazing ones I can think of would be available.
Managerial wise if we're really going for an amazing season we need to strive for someone special. Hiddink or Mourinho, maybe Pellegrini.
That is all, of course, if next season we're going to go for it. If we're content to slowly build up, and have another so called "transitional" year, then Essien, Lukaku and De Bruyne would certainly do wonders. There are plenty of managers good enough to land this squad a top 4 place. I personally have a soft spot for Moyes.