The problem is they did not take away buildings people paid for and removing GB's is just that and that's a great way to make your paying customers angry.
Removing any bonuses you get from attacking would simply mean your troops would get nearly destroyed if you face a equal level opponent and this would kill off pvp to the point of where the only people that could take part in it are diamond players or people who have built only military buildings and houses to supply the population needed for them and that's it.
I prefer people to have the ability to take part in pvp in a game advertised in it otherwise if a attacker can only do 4-5 equal level battles then no one would attack unless the reward is increased heavily as right now only attackers suffer troop deaths.
Yes some balance is needed as you should not be able to do auto each battle and win against equal level opponents but attackers need to have a bonus to keep people actually taking part in pvp or you will kill the game completely and you might as well make the game farmville and only have the city builder aspect of it.
That's not what many are here for.
Look at the responses here for why many feel the same way I do:
http://forum.en.forgeofempires.com/showthread.php?22040-Offensive-amp-Defensive-Great-Buildings
Yes some kind of minimal damage is needed for equal age battles to prevent autoing but wiping out your troops on each battle when the AI is decent even with the correct strategy is what will happen unless the defender suffers as much as the attacker.