If he improves the talented squad we've got then we should be competing for the league and be close in the cups.
It's a bit naïve to say Mancini was sacked because he didn't win trophies this season, I would say it was more because the squad has gone backwards.
As has been said Mancini wants to spend money each season (100 million ish) and that just isn't sustainable. Mourinho also operates in a similar way to Mancini, which is why he is not the answer.
It appears as though the new Spanish lads have used this season to assess where we are at, and have decided that both the way the football is played, and the way the youth players are developing isn't good enough. To be honest I agree with them. I just hope that the steps they take now will prove to be correct and we become a better club, and a more successful one.