You can't claim a map isn't balanced because one side plays smart then admit the other side looses because they are noob level...
If sides are even, it's a hard map for attackers, I don't see what is wrong with that. Some maps are biased towards the defenders, some the attackers. If you play Campaign, it's common knowledge which are which. Unless you're on a tournament paintball field, no map will be exactly even.
It's still winable and with even teams, often goes down the fierce fighting at the last cap. If teams aren't balanced, it can be a steamroll either way, just like any other map.
It's not the maps fault or the weapons, it's the teams.