Pochettino was never that bad to the extent of sacking him that way, his plans and reshaping of the team was about to kick off before his sudden dismissal now it is left in the hands of Maresca and it is absolutely going to be a fresh start for the team. We expect more from Maresca, we keep seeing his signings and we just have to believe in him to be better than Pochettino not just by signings alone Ike the way Pochettino did and couldn't win a trophy.
See how Pochettino handled Chelsea until the first half of the season was a failure because most of them lost rather than won while Pochettino was only able to rise in the last few matches this did not give him any chance the club manager already knew what to evaluate, with the new manager Maresca maybe Chelsea will be better at the start of the season.
And Maresca will not fully fulfill the expectations of Chelsea's manager, he also needs a longer adaptation to see the team's situation get better, therefore with the hope that the new manager Maresca Chelsea will return to competition even though I myself am still not sure.