If you have both the Axis armies vs both the Allied armies it can often be an enjoyable and balanced match with all the players being vital to the success and failures of each team.
For example with the British and Americans, its a cause of holding off the Axis attack whilst slowly moving up the map and at the start of the game the yanks really have to hold them off until the British can get their defensive guns up.
The Panzer Division on the other hand can steal the game in an early rush, however without backup from the Werhmacht troops they often find their army wiped out deep inside enemy territory.
It limits the scope of options for an attack plan really with the Axis basically being told to relentlessly attack the Allies but it still feels extremely fun and rewarding.
Of course, to even try this you have to assuming that Relic Online is actually working which in my experience is generally never. Damn outsourcing.