*Puts on historian hat*
It's my observation that the biggest obstacle to Jedi gathering on any RP board is the narcissism of small differences. They broadly agree that Light is the way to go, all pay at least lip service to the canon Code, and generally try to do good, and you would think that would be enough. But Jedi factions tend to emphasize the little things as a way of maintaining their identity.
Take, for instance, whether or not Jedi should actively be involved in war, or even something so simple as marriage and families. What should be a relatively minor disagreement over doctrine gets treated as all out blasphemy, and IC differences collide with OOC egos to create a perfect storm of salt that poisons any attempt to unite. In one memorable instance on an old board, a Jedi writer politely pointed out that the primary Jedi faction had become so insular, it was effectively impossible for anyone to write with them. They promptly threw a fit, declared all the other Jedi heretics, and left the board.
Darksiders in general and Sith in particular tend not to have that problem. They have a common goal, and they more or less accept that backstabbing and betrayal are part of the game. All they really need to unite is someone charismatic enough OOC and powerful enough IC to get a solid core working together, and since success breeds success, anyone else looking to gather some scraps of power jumps on the train and they railroad over the opposition. They don't worry about the little things, they just kick the crap out of the enemy until they've accomplished their goal, at which point they go back to kicking the crap out of each other until the next time the hype trains gets rolling.
Perhaps that's the approach you guys should take. Not the backstabby bit, but the part where you get a solid core of writers together, people who are well known and respected, and show people that you can put aside the little things and work towards a greater goal. There's nothing wrong with the sort of loose confederation you're discussing, but there's only so much it can do if the other side gets the hype train steaming along again.
