I certainly agree with the last one. Bridger talked about a nice idea in a pre-OF podcast, an "assault" mode. The game started with one player having much map control, who was supposed to defend his territory. He got like ten minutes or something to establish his defence. The other player played the attacker and assaulted his defences. A countdown timed how long it took the attacker to reach a certain goal. Then, there was another "round" where the roles were switched; the previous defender attacked with the same faction while the previous attacker defended with the same faction. The second round, however, would only go on for as long as the first one did, which would make it semi-balanced.
At first glance, the really offensive factions like PE might seem really unwanted because you'd have to defend with them as well. It would do, however, because you'd only need to defend for as long as it took you to attack. It would really test your skills of all kinds, and yet give plenty of variety in strategy.