I think you are wrong to call Chelsea's squad bad... They have good players in both defence and attack... The club's problems started not because of the players but because of the change in management and coaching staff... If the new coach turns out to be a good professional, he should have no problem getting Chelsea to play well again...
It's true, Chelsea has good players, and even the Blues have signed a lot of potential players this season and spent a lot of money, and the question is, why are they in this slump when on the other hand they have no shortage of good players? I have several assumptions about this, in my opinion, there are three problems that are the contributing factors to this happening. First, they can't be united, as many as 17 players have been brought in to Chelsea and unfortunately they haven't been able to unite because they still need time to adapt to the team so cohesiveness is difficult to achieve. Second, the front line looks dull, Potter is known as a coach who always relies on the 4-2-3-1 scheme, this scheme requires the line-up to have a sharp and qualified center forward. but so far Chelsea has not been reinforced by a striker who is really capable of carrying out this scenario.
Felix, David Fofana, and Pierra-Emerick cannot be relied on as goalscoring machines. And this situation made Potter entrust the front line to Havertz whose original position was an attacking midfielder, thus making the attack not optimal. Third, Potter is a coach who is not respected enough, Todd is too brave to entrust Potter with a club as big as Chelsea. I see that in the history of Chelsea, there are usually coaches with big names and brilliant achievements, but this time Chelsea was coached by a coach who had never won a championship, namely Potter. I hope Pochettino's arrival will improve Chelsea's situation in the future.