I think it's pretty ridiculous to make a monster with good drops and continue to make him more and more unkillable. The game ceases to be fun when you have no shot at beating such a monster.
It's good to have a challenge, but making it impossible is just stupid. Sea offers very little to the player as it is. It take about a month of prep work to fight JoL. Even after beating him, AV seems to only pop about 1/10th of the time. Beyond that, they make him absolutely impossible to beat?
How is that fun? SE needs to learn a good reward for work ratio. Outside of what AV would drop.
Each of the the Jailers can drop a torque. You wanna know what the drop rate is like on them? My LS is
0/17 Fortitute Torque
0/21 Temperance Torque
0/7 Prudence Torque
That's just a little run down. The only other drops are virtue weapons, which aren't very good for anyone. Also, the pop items to pop higher tier jailers aren't 100% drop either. It's frustrating to farm several tier 1 NMs to pop a tier 2 NM that doesn't drop the pop item for JoL, which forces you to start over from the beginning after getting zilch to show for hours and hours of work.
The other decent drops in sea are the 3 mage capes (horrible drop rates from Ix'Aerns) and Novio/Novia (which are a horrible drop rate from JoL).
Overall, sea is just messed up. It isn't even so much of a challenge as much as it is a job. Making an NM hard is one thing. Making him in possible is just stupid game design.