Hmm, a few modifications are needed, are they?
How about
:
*You cannot sell skills that are known by any of your characters.
*When you sell a skill or item, you do not get "Balthazar Faction," but rather something else, "Refund Faction," we'll say. It can only be used to unlock skills and runes, so it cannot be used on Zaishen Keys or Tournament Tokens.
*You can only sell skills/items that were unlocked originally with Balthazar Faction or Refund Faction.
*Selling skills/items does not give 100% of the original faction, but rather some amount less, so you can't circumvent the Balthazar Faction System altogether. (I certainly wish we could have it at 100% so we
could circumvent the system, but Anet made the unlock packs, so that is now impossible.

)
Would the idea work like this? Or did I miss something?