Maresca is trying to change the team at his own discretion, Pochettino also allowed many players to leave the team after his arrival, I think it is normal when a team changes a coach. I understand that after Maresca managed to win the Championship with Leicester, he feels confident in himself, but the Premier League is a completely different level. He says that he wants to achieve the same greatness as City, but it will be much more difficult to repeat than to say so.
Having that been intention to achieve greatness just as he did at Leicester City is a good naive towards making the team great, but it will never be easy for him especially in the Premier League where there are many mangers and many teams with good and quality players and squad depth than Chelsea.
He will have to undergo some disappointments along the line because he can never achieve exact what he want in Chelsea as easy as he may expect but he can try to make it to the Champions League another season if he can be able to achieve that, then he can be among the title contenders another season.
Nevertheless, we cannot conclude because some coaches do have luck to make it in their first season which we have seen on several teams, I will expect a top four for Chelsea and nothing more.