I think they need to add some kind of rewards for clearing Stone sky sea.

It really does serve as an eye opener if your rotation and gear are seriously bad. However a casual player has no incentive to participate in this content and the potential exists for them to continue playing oblivious to the fact of just how bad they are.

If casual had a reason (like glamours) to take on stone sky sea challenges then you might have more people realizing how bad they are and least be aware of the fact that they need to improve and hopefully choose to act on it.