Michael, it's not just people on the East side who will suffer. When they closed the gate on platform 2 for maintenance purposes (yeh right), platform 2 became extremely crowded and IMHO quite dangerous following a bit of argy-bargy on the platform.
If they have Oyster barriers at the bottom of the steps these will have to be manned for safety reasons. The only way the station will be able to close them off will be to keep the gate at the top of the stairs locked. It's my guess the powers that be will not want to man these barriers too often, therefore the gate at the top will be more than often locked.