My best guess is good runs with strong teams top out between 4 to 6%. Mediocre teams are probable 2 to 4%. Basically, if your guild was mercing to spread out rewards, or using heavy hitters, my threshold guess is about 20 players hitting 5% per phase. For a roster with 4 GL's, this should be easy. It will be a lot harder for small merc bands to carry a raid though it seems.
Also, agree with everyone else that the rewards on the aero's should be flattened. Make the "reward curve" with gear or currency, but flatten the aero's.
