Another way to look at players getting 1st Team Reps is they have earned the opportunity to get those reps. If a player lower on the team pecking order is struggling in practice, his opportunities with the 1st Team unit, on the side of the ball he's on, will be very limited at most.
Pete Carroll was the Head Coach of the Jets for one season (1994 season). Aaron Glenn, a 1st Round Pick by the Jets in 1994, played under Carroll as a rookie. He certainly is more familiar with Carroll than the vast majority of current coaches in the NFL.
It's good to see Aaron Glenn get recognition for his Coaching. I'm confident Glenn would produce good overall tangible results as an NFL HC in a good organization.