What class makes the most difference in Crystal Conflict?

[AlanJust]

Been stuck at Gold forever now.

My Win/Loss ration seems to be exactly 50/50.
I play warrior and nearly top Damage-Dealt, top Healing and top Damage-Taken every lost game.
I place markers, shout what target I'm after and always keep + on the healer.
It is getting to the point where I know a which team will win a few seconds into the match.

So anyway, I was looking for the class that creates the most impact on the win ratio and looking at the Ladder I see many Dragoons up there but I was thinking of Ninja to try and quickly kill the enemy healer. I am also willing but rather not play the healer, yet again, if that's the difference between win or a loss then so be it.

What class do you play and how much difference do you make?

Edit (Class=Job)