There is a way to avoid that kind of retarded alliance.
At the end of each Strat season only 1 faction wins. They'll get reward and glory. The second one, will have nothing, too bad for them if they are stupid enough to be allied with the winner.
We could imagine something like 100k gold and/or a special item (a crown for exemple), or a title for each member of the winning faction.
It could be fun to see all Drz get rewards and Kapiz/Greyz just being fucked up (this is just an exemple, who knows who could be the winner).