Stage A-b-c-d-e
Both team start at stage C and the winning team gets to advance into the enemy territory the next game. To win you have to win the game at the enemies home base, in this case E or A. Just by implementing something of the sort you can really vary the gameplay for either a continous (keep hero and levels at the next stage), Reset the levels after you win, or decrease/increase leveling speeds.
This would be a great idea! Maybe have the winning team that is pushing against the enemy have a increased spawn timer to make it harder to push forward, or the defenders have an decreased spawn timer to help push them back. Maybe you get a certain buff while you are fighting in your territory while you get a debuff while fighting in enemy territory. These buffs/debuffs could coincide with the demigod/general you are fighting with/under.
But I'd also like to see some type of ladder system that has a much slower leveling style. What I'm trying to explain is something like Diablo II's ladder system.
While I totally agree with this, I love seeing ranks and whatnot because it gives you something to look at to see how you are doing, it would be good if the bonuses were just aesthetic in nature. Instead of getting say a cheap OP spell or ability, you could unlock a new demigod, general, or assassin, who is on the same playing level as the other characters. They wouldn't be OP, but at the same time would look so awesome as to inspire awe and maybe dread at the sight of one!
Edit: Fixed