What it should be is that the first stage will always be in the attackers favor. This would mean they get armor when def gets none, their spawn is closer, better cover, etc. Then, as you progress through stages, it becomes more defender biased. So defenders get armor when attackers get none, better cover for defenders, etc. One thing I will say is that if one team gets a helo, so should the other since the maps were designed just so amazingly well and helos let players reach otherwise inaccessible areas.
This can actually be seen on Eastwood and Blackwell breakthrough. In general, the first point is quite easy to capture, the second is kind of a pain for everyone, and the third is difficult to take. This is also hard to notice sometimes because both of those maps suck.
