Its been posted before, but here are the main concerns with adding an organization to the Primary Leagues.
1. Recognizable fighters. An MMA fan will know who 95% of the guys fighting in UFC are, which makes it more fun to pick fights and allows for intelligent debate on our forums. At the moment, no other organizations can consistantly put on cards at that level.
2. Reliable fight cards. Nothing pisses me off more than taking the time to research two fighters, making a decision, and then having the fight be scraped. It happens everywhere, but a professional organization will have their card posted well in advance, and have that card remain intact up until the event.
Some organizations fail in one or both of these catagories, and with it be a turbulant time in MMA right now, its hard to see who will emerge with quality shows, and top name fighters. Once an org can meet both of the above criteria time and again, we'll put them in the primary. Until then, we've go the secondary league to fill the gap between UFC shows.