There are 25 mobs at one time available there with the respawn time of 104 sec. If mobs are constantly killed it's almost 2600 mobs during the event. Each mob drops a stone. Accumulated stones can be exchanged to very good rewards.
Event was created as a pvp fight for the mobs, not the one for mobs free farm. Rewards are good, there are pretty many mobs at the location so fight for them or leave them for that 40 people and they will get a good profit, leaving others with nothing.
Come and win or loose a nice chance to obtain tokens for exchange to valuable items.
It's an interesting position that you guys put yourselves in. On one hand, the event doesn't seem like it spawns enough mobs when there is a hundred players there. I mean, that's typically the response anyone would give when the amount of people outweighs the mob count 4 times. However, my friend, Testicruel, said that he got over 110 of the stones after farming for a short while. He got bored farming and stopped, but he easily could have gone longer, easily getting another 100 stones. That's two whole Lucky Sunpoints, or ~5k profit from 30 minutes of farming, which is actually insane.
So here is the actual dilemma, that which people are complaining about:
The spawnrate is normal and the amount of mobs is equal to the density of mobs in the area. When there are a lot of players, the density seems too small. When there are not a lot of players, the density seems too big. The amount of time the event lasts is 3 whole hours.
IMHO, this one seems pretty clear-cut. Players will never be satisfied. If you think there are too many players, then wait until some leave. Think of your favorite farming spot. Of course people know about it, and some people will farm it, but you don't come to the forums complaining about how your favorite farming spot is taken up by someone, do you?