Naaga overall, thus the pet system, needs to see some changes overall to make it more accessible to mid-level players trying to evolve their pet.
Naaga is not an end-game dungeon, but was highly exploited by end-game people while things like Azrael, Aqua, and Baroness are available, for example.
In most cases, people get to the point where they're doing Naaga comfortably after they've already put the time and money into evolving their pet, basically making this dungeon more high-level than it is.
I've no idea how, but at the moment Naaga's only rewards help players evolve their pet (since Exp. Wine was removed). There needs to be a change that would prevent people from taking control over the entry tickets, I guess. Only 3 nolifers (or even 1 if they manage to control the respawn time) are enough to block the entire server from running Naaga.
Most people dislike only buying something that they have the possibility to farm.
I don't know, can't talk more about it since I don't know the specifics. I would love if the team shared with us the average number of Naaga runs done per day, the average number of keys farmed per day, as well as the average number of sold keys per day. Or at least they could use that to balance things a bit. Cheheom souls are still in low number of the market - the base issue is that most players stuck around the under-mid-level bracket don't know about Naaga/Treasure maps.