As it stands, Withering Reduction is grossly unfair. The XP penalty is applied to caster classes (or those who get their hands on a withering device), so all the penalties are taken upon the caster and none of it is given to the individual who actually gets their withering reduced.
The XP penalty is there, I am sure, to represent the life energy that is lost to reduce the withering. However, I would make the following suggestion-
Make the option available for the cleric to TAKE the life energy of the person who's withering is getting reduced. Or split it even, so both loose 75 xp.
We are seeing fighters, barbarians, rangers, reaching the higher levels, yet clerics who are forced to reduce the withering of their converts (to keep them converted or display the benefits of faith) are being subjected to increasingly difficult XP demands to meet as they level up. Giving the option for the cleric to remove the xp from the supplicant will even the playing field and make the XP burden much easier to bare.
Plus it will make playing greedy clerics more fun. :)
EDIT: That, or make the person who gets their withering reduced loose 150 xp as well.
Maybe give withering reduction from a cleric a piety reward? Also stop allowing non-wildling characters from turning in fey crystals for wildling withering reduction would be nice too to keep it fair.
Make both caster AND castee lose xp:
I dont get why the withered subject gets away free, I mean there should be some strain upon somebody once heavily withered going back to normal.
Working to make the withering weaker, that'll save you more exp in the long run. You were the main proponent for making this withering deathly powerful to begin with. REAP WHAT YOU SOW.
I am in favor of powerful withering.
I am NOT in favor of making it entirely one-sided however, all classes should be penalized for getting it reduced. :P
Quote...yet clerics who are forced to reduce the withering of their converts (to keep them converted or display the benefits of faith) are being subjected to increasingly difficult XP demands to meet as they level up.
Find a way to tip that balance into your favor. You are never forced, you have the power to reduce the Withering. It should be rewarding to you and that doesn't come from any mechanical changes. Demand something from those that want to be healed.
My Cleric of Vergadain has paid for a Dwarven Brewery to be built main from a bit of trading and asking for lots of coin for Withering Reduction.
It was an xp hit but a great deal of cool stuff came from it.