DICE are adamant on trying to compete with COD with Close Quarter combat and this would keep both sets of players happy. You could even go further still, have three flags to capture as per the original map and to every one outside the building it appears as a single flag colour depending on which team controls 2 or more of the three flags inside the building.
This would keep the BF fans happy, with open maps and vehicle warfare and the COD players happy with close and tight gameplay. without having to sacrifice game mode or reduced map size. This would also stop Helicopters massacring everyone at the top, with plenty of places to still play inside, away from the heli's attack. Obviously with the tower collapsing, the top map would be gone and its back to normal.
Its an idea, its up to DICE to decide if its worthy or even practical.