A little anecdote, not about establishing who has control, but more about understanding your student!
When I was "in the circuit" during my PPL I flew with an instructor who rarely moved his hands more than two inches from the controls, and would tend to take over during the last part of the landing, when I screwed it up!
I bumbled around the circuit time after time getting all the bits right, except for the last 50 ft when it all seemed to go pear shaped, and my trusty instructor saved the day.
Then one day my usual instructor was not available and I went instead with another guy.
First circuit, as normal - OK until the last few feet when I had the usual trouble.
Second circuit, short final, the instructor sat back, folded his arms
and said the words I'll never forget: "don't just f****ing sit there, do something"! The ensuing landing wasn't pretty but after a couple of bounces we went around for another go. Things got steadily better, with the result that I went first solo at the end of the hour!
Afterwards, my instructor explained that he noticed that I was visibly relaxing (didn't feel like it to me!) as the ground approached, as I unconsciously expected the instructor to take over. So he decided not to!
So the moral is: whether or not you're too hands on depends on your student, and identifying what is needed to both be safe and progress his skills.
Amen.