Manuel Pellegrini must deliver five trophies in five years at Manchester City says chief executive Ferran Soriano

Manchester City's chief executive, Ferran Soriano, has declared that he expects at least five trophies in the next five years from the club's next manager, who will inherit a stronger squad than Manchester United's – and one which should "absolutely" have retained last season's Premier League.

Manuel Pellegrini, who is 59, is expected to be revealed as City's new head coach within days and Soriano, in his first briefing with the British media, said that the squad now needed an older leader who knows about man-management because it would be impossible for the club to win the Champions League if they did not possess "a group that behaves like a family… where everybody respects everybody". He said the City squad, known to have been at odds with the confrontational former manager Roberto Mancini, was "difficult, only in the sense that it is diverse in terms of nationalities and languages".

With momentum lost under Mancini last season, Soriano would have sacked the Italian even if he had won the FA Cup for City. "We can lose the final of the FA Cup, disappointing as it was, but it is not about one game, it is about whether the football we play evolves properly," he said. Mancini's frequent public criticisms of City players and ancillary staff were "something we don't like" and entirely unjustified. Mancini had a squad "that should... not be kicked out at the first group stage of the Champions League," he said.

Soriano said talks would take place with Carlos Tevez and Gareth Barry – two "very good players" entering the last year of their contracts – and that work was well advanced on purchasing new players. Fewer than six would be bought this summer and there is absolutely no chance of Sergio Aguero leaving for Real Madrid. "He's not leaving," Soriano said. "This has gone on and on. He has never expressed the willingness to go. We have never had an offer and if we had an offer we would say 'no'."

Though he did not name Pellegrini as Mancini's successor, Soriano sees the Chilean as an individual capable of helping oversee the introduction of a philosophy of football, like the one introduced at Barcelona during the chief executive's five years there from 2003. It will be based on a high technical standard of football and a core of players, such as Joe Hart, steeped in the club philosophy and who can teach it to incomers.

Pellegrini will not face demands for immediate success but Soriano will want to see that the new philosophy creates a momentum which ensures trophies will come quickly. "Next season is going to be much better," Soriano said. "It doesn't mean we are going to win one or two titles, but if we look at the next five years and I could plan now, I would say I want to win five trophies in the next five years. That may mean we win no trophies one year and two in another but, on average, I want one trophy or title a year. I think [that is realistic]. If next year we don't win, but progress our football and get to the semi-finals of the Champions League, finish second in the Premier League and lose the FA Cup final again, that will be fine. That is because we will have progressed in the way our football develops."

Rejecting suggestions that City's two managers in five years placed them at risk of being as short-termist as Chelsea if the Pellegrini move fails, the 45-year-old Catalan argued that the natural three- to five-year cycle of football management made a change after three years perfectly acceptable.

"It is totally unfair to compare [us with Chelsea]," Soriano said. "I don't know how Chelsea operates, that's their problem. But our behaviour and our approach to management has been appropriate. Teams have cycles and you can have managers who go through several cycles and managers who go through one cycle. Three, four, five years is one cycle. Maybe a manager can do one or two cycles, but people get tired. Players need another way, another [type of] excitement, and managers also want to move. This is normal."

With Pellegrini being asked to work under City's director of football, Txiki Begiristain, Soriano said – when the notion was put to him – that England may have been slow to adopt that management model which provided continuity amid the continual flux of managers. "I think it's arguable [that England has been slow to adopt the new model]. It's hard for me to see the problem [with it]."