I really want to see the day where a Poly ninja farms insanity. Until then I wont believe it.
And regarding Shaman/ninja outdpsing Warriors in forest... we're talking strictly here about endgame, Up until Forest, Warrior dominates all fields and all maps.
Not to mention that Shamans and ninja's only shine on Bosses in Forest and Metinstones.
In other words what I'm trying to say here is that you're gonna have a much harder time progressing up until forest without a warrior/Sura. So basically Even if current Market availability is not part of the balancing, you're gonna have a much harder journey getting to Forest without a warrior Main farmer.
So we're coming down again to the Meta. Make Warrior/sura, Farm gear and enough yang, Swap to something else if you want more damage in end game, which again its about play-style and time investment into the server.
Also we're comparing here only metin stones in forest at the moment, if we take into factor Any Dungeon or Content 95% of the time you will need a warrior in order to complete that, otherwise you will lack the damage.
At the end that is my point of view and opinion, doesn't have to be true or correct. It's just my take on how I see things on the server currently.
All in all every class and spec have their own field where they are strong, and weak at the same time.
Note. Warrior with Full event push like Pierce boost etc... Will always be the highest Top possible damage in the current balancing of the server.
Would also like Opinions from others as well, to see their point of view on this topic.