What about 2 permanent factions + 1 mercenary faction. That you decide on the charpage on the website.
Mercenary faction will get a small-large gold bonus for being put to use wherever they are needed.(Teamswitched possibly every round)
The other same as before. Only you always fight for your own faction unless mercenary.
This way the clans can always play together, you get better teamplay after a while, and prob some intense love-hate relationships
Ithink there would be enough people that chose merc for it to almost always work out.
New possibilites, permanent TS channels for each of the 2 factions.(For those that like such), great leaders will emerge, and maybe with the same people playing together more often, it will start resembling 2 armies doing battle, instead of random hooligans brawling.