Map is advantageous for alliance if they push offensively. Map is advantageous for horde if they are initially defensive and prevent the initial zerg.
Nothing has changed with the premade prevention when it comes to win strategies. Premades were winning quite effectively against horde with their zerg strat until horde began making changes in their tactics.
As gear scales you will see alliance begin to win more because the maps shifts more toward pve race. They will go back to avoiding pvp engagements and not need a single tower or GY because it will be a deathball to drek and kill.