I would like to suggest that somewhat low, flat rates are instituted for dying equipment. Because of the inability to determine the colors of gear dropped by enemies, players are forced to choose between using the best gear they have available or looking absolutely terrible. Because the color of your gear is a purely cosmetic aspect of the game, the cost of it should not be prohibitive.
If KI has a specific reason for the cost of dying gear to be so high, would they please explain the reason?
I think the large price for dying clothing encourages more people to play the game even more. If you want to dye your clothes your going to need a lot of gold and the way to get more gold is by fighting more enemies. Its just a way of giving people something else to do, so they wont get bored and leave the game.