It is only first step, dropping the underperformers, and with Casemiro in the building, Bruno for example can be dropped with Eriksen preferred, I do not mean that Bruno was bad vs Liverpool but he was bad vs Brentford and still was not dropped, probably due to the lack of option.
I do not want to see any player being a guaranteed starter, even Varane & Martinez, as long as they perform well consistently, then they are the starters, otherwise, Maguire will be given his chance again, same as our attackers, assuming the starters are Sancho+Martial+Rashford, if they underperform, then Ronaldo will be given his chance, maybe a new signing will be in the starting 11 (Antony or Gakpo).
What I want to see from Ten Hag is that high standards must be maintained at all times and no one is exempt from banishment to the bench.
Btw, I am not making a case for Maguire to be given a chance or restored to the starting 11, it is just an overall point of the players knowing that they have a place in the starting 11 only when they consistently play well.