I think their is a difference between a map that is balanced towards one side,which is the way it should be,and one where its common to fail on the first capzone.
Considering its rarely played its hard to tell which it is!
Play it more often. You will find that most frequent occurrence is lock down at the first cap zone.
I can get behind the idea of unbalanced maps that make it more satisfying for the undergod team to win, but there comes a point where it just becomes predictable and boring to play that map, knowing that most of the time one team will win, I am sure everybody has fun playing Mamayev with the Axis steamrolling, Saipan for Allies, or some of the other maps that played differently before the last update (I think most play exactly the same now, but I havent played too much since then so I am not sure).
For me, a map might be hard for one team, but there has to be a good possibility of winning or it just becomes demotivating.
Mamayev is well designed so even when the attackers nearly always win it is still fun.
Mamayev favours the attackers because it gives the attackers three spawns to chose from so they can easily flank.
On Mamayev ALL OF THE OBJECTIVES LOCK WHEN CAPTURED! This is fundamentally the best way to design a map because it helps to ensure that the whole map is played, or at least avoids bogged down attacks at one cap all round, which is boring to attack and defend.
Maps like Stalingrad where the most frequent outcome is the attackers being bogged down at one objective and being mowed down for the whole round is an illustration of flawed map design.
If Stalingrad were designed to play like Mamayev it would be much improved!
Maps should be designed such that the whole map is played most of the time instead of 25% (fact - A) of it 75% (guesstimate) of the time.
It's not rocket science...