[DesolateRestriction]

The cash shop idea is good when you first look at it, but there's several problems just from the start:

A lot of different people contribute ideas into the making of NPC(s).
You have ganis, gfx, scripting, and even concept design (the guy who had the idea in the first place.) Very rarely does one developer do all the areas, so who gets what? And how would a Levels Design developer benefit?
(You can't put levels in a cash shop.)