I have finally returned to SG after a year in the wilderness. PB is great but the aerobridge queue does make it a bit of a let down. So is it possible we have things the wrong way around? Wouldn't it be easier to start with a general boarding call for the REAR half or two-thirds of the aircraft? That way status pax (who sit in the front) would be invited to board once there was less of a queue and would make the most of lounge time.
This already happens if you are CL, as you board at the last minute when the lounge attendant comes up to you and invites you to board.
As a WP in the past, I would deliberately wait (particularly in CBR) in the J lounge so I had less time in the queue and on the aircraft, unless flying J or with a roller bag. But I acknowledge CBR is a unique case as everything is so close.
You could still allow premium pax to board at their leisure, but maybe have 2 boarding announcements - one at the gate, and one in the lounges for status pax. The queue would also be more efficient because the whole length of the aircraft aisle(s) would be being used, instead of the inefficient scattergun manner things happen in now.
I acknowledge this isn't perfect and would require carry-on size enforcement as well as making sure people don't use bins in the front half of the aircraft. I noticed yesterday at MEL for my flight to CBR that 2nd smaller carry on items were being tagged at the gate so they would be stored under the seat in front, which is a start.
As an aside, I really hated my US flying experience, particularly all the boarding groups. Even status pax would be standing in the lanes for well over half an hour, sacrificing quality lounge time, just to fight for OH bin space. So stressful, I just started checking in my small roller bag instead.