because it wasn't means to be done like this, maybe?

the B rank was means to be solo monster, now they are for a small group (can be duo with chocobo)
the A rank was means to be done by a small group, now it's a full group (it's still 8 people)
the S rank was means to be done by multiple group, it's still the case, but frankly i'm kinda sure it's around 24 player...

there you are.... more of 100.... you don't see the trouble?