That's only with hindsight. I'm sure Fergie went into last season, assuming Hargreaves would have a part to the play in the season ahead.
Turns out we coped ok without him but I'm sure Fergie will be aware that if we did have a player with Hargreaves' qualities available last season some of those awful away performances might have been a bit more convincing.
I agree that 6 central midfielders should be enough enough but I don't think Jones will be counted as one of those 6. He's even said himself that he doesn't really see himself as a midfielder.
I think Fergie will want to start the season ahead with the same number of specialist central midfielders that he started last season.
i.e. Scholes, Gibson, Hargreaves, Fletcher, Anderson, Carrick becomes:
Fletcher, Anderson, Carrick, Giggs, Cleverley plus A.N. Other