Been playing AH & AH2 off and on since at least 2004 and the gameplay has stayed the same. GV's "towering out" make up for the lack of overhead cover and other obstacles which would normally protect them from the prying eyes of an A-20 at 10,000 ft There is also the issue of bombers having the "cheat" of knowing the exact layout of every base in the game and knowing where GVs will spawn in.
If they are towering out when you drop on them, maybe you should try different bombing tactics. The carpet bomb attack in Lancasters at 1K over a GV base is pretty old and used often. Try doing some high altitude bombing or diving in from the sun from 15,000+ ft. Less chance of seeing them tower out as there is a better chance of them not seeing you.