I kinda thought for all the money spent and rebuilding there’d be some operational improvements. I’m sure when 1,2,3 were closed I didn’t ofyen notice a tailback. It feels like it’s only back since the new platforms opened.
There wouldn’t have been a tailback, as none of the trains were calling at London Bridge.
Given all they've done, and all the money spent, I'm surprised they didn't add a fourth platform for Cannon Street services. It seems like some space could have been found from Tooley Street, perhaps at the expense of part of the top floor of The Shipwrights Arms, but given what they did to The Wheatsheaf this doesn't seem like something that would pose much of an engineering challenge.
A fourth platform would have been right out over Tooley St itself, also Bermondsey St and Holyrood St. Not at all practical. Even then, as others have said, it doesn’t solve the actual problem which is Borough Market Junction. To solve that you need a new track there, and that means going into Southwark Cathedral.