Why not help mid size clans(and your own pockets) by making Netherking openable with 600 circles? This would make it possible for 30 clan members to spend a few dollars, rather than have a few members bear the cost. Seems like a reasonable request, wont take much programming on your part, and will increase your bottom line.
What the heck? KaW should implement additional currencies instead. Like I'm talking multiple bars that require the purchase of several items to open Netherking. That'd be the most efficient way for the devs to milk this cash cow. Good times