IMO, I think the punishment (dropping an in-form player from the starting 11) is a severe one, however I agree with it, because at this stage of Ten Hag's tenure with the team, he is required to develop the team in many aspects such as the technical aspects, tactical aspects, mental aspects, physical aspects and discipline, which means mating out severe punishments for small infractions is quite necessary to raise the level of discipline, the hope here is that in the future, these little silly infractions are stamped out from the team and a top discipline level is the default setting.
I also agree with Ten Hag's approach with Sancho, he thought he was not in the best physical and mental shape and probably needs some sort of special program away from everything.
Ten Hag still has alot of work to do, but I am happy with his work so far and where is the team now.