Roundhouse, Downfall, seelow and Outskirts have always had them, but they were uncommon maps. It used to be that you'd get Airfield, Hanger, Dome, Cliffside, Upheaval, castle and Courtyard for TDM, Dome, Hanger, Courtyard and castle for Free for all, Seelow and roundhouse for capture the flag and downfall and outskirts for search and destroy.
You;d obviously of gotten them all on all modes, but those were the common maps, now you get downfall loads on TDM and rarely airfield :(