I think it is in the best interests of those who have leveled their Disciples of the Land (arguably the most difficult type of class to level, given their current state) to not have these mobs dropping plentiful Cobalt and Rosewood. Players should receive some other types of rewards.

It could tie-in directly to Grand Companies, who have an interest in defending their city-states from vicious monsters. players could receive licenses of some sort to go out into these wilds and kill these monsters. These licenses could either be temporary (given to players in exchange for seals or gil) or permanent (given to players when they reach the next rank in their grand company). Players would, in return, receive seals in amounts based on 1) How many monsters they killed, and 2) How high level the majority of their prey were. Players could also receive titles as a reward for racking up a high-kill count during hunting season - such as "Master Hunter/ess", "Jaegermeister", or "Master of Beasts" + a Grand Company related title (Maelstrom's Marshal, Adder's Avenger, Fiery'n'Fierce) -- these are all crap, but you get the idea.

They might even received rewards in the form of new GC gear. There's a lot more that could be done with killing these higher level mobs than free materials that will just flood the market.