Just an honest question for the DMs here, why does it matter so much when lots of people pre-board? In my experience, most GAs give them enough time to board and be seated by the time they call DMs and FC, so there isn't some huge backlog on the jet bridge. And FAs do a good job of preventing coach passengers from using the FC overhead bins.

EDIT: To clarify, I'm specifically talking about flights with a large number of pax pre-boarding. NOT pax who board outside their zone.