Do people even follow the boarding order? Sometimes I can't hear what they say and I just get in line anyway, and I've never had an issue. Obviously people mostly follow it, and it wouldn't work if nobody listened to it, but I'm not sure that the gate attendants care if a few people queue at the wrong time.

Also, queuing order is only about who goes first. If you're in an early section, but show up late, you can still get in line. So in this proposed system you can still have window seaters showing up late and defeating the whole point of having them board first.