Well, certainly the current system has to be changed. In my games, nobody uses anything from any book that has an XP cost. No crafting and none of the spells. Maybe my two DMs should houserule something here, but they haven't, so we just don't use it. Instead of making a spell require a sacrifice, we just don't ever cast it. Crafting and any spells that require XP have effectively been houseruled out. So I'm really glad to hear about the Pathfinder decision.
That said, I have a couple balancing suggestions. I like the poster above's ability damage suggestion. Something like 1 con damage/1000XP listed, or 1 wis damage/500XP listed. And it would have to heal naturally. This way, magic item crafting would only be done during downtime, and wishes would only be used in dire circumstances, or in downtime. There could be a mechanic where going beyond this doesn't kill you but drops you into a coma until you are healed. The DM can control the power jumps from crafting or wishing by limiting when they can take downtime. If the world is going to end and only you can stop it, the Ring of Wizardry can wait. So you have to save the world without it.
What I've been contemplating is a "pool", somewhat like the artificer class, that spellcasters draw from to make magic items. The less fiddling with "XP costs" for existing items, and at the same time keeping it simple and elegant would be the primary concerns.
Something like perhaps the 1st level spellcaster having 1/100 of the XP needed to get to 2nd level in his pool - in this case, 10 "pool points" to spend on scrolls, potions and the like.
Or it could be simplified even further somehow. "You can make X magic items at this level." Perhaps with one-shot items being like ammunition, allowing you to make, say 5*, for the cost of one.
* using this because 5 charges/day is the maximum number of charges you can get out of a "charges/day" magic item.
It always felt like a triple penalty to me. To craft an item, you've got to expend a feat (and feats are many thousands of times more valuable to me than some paltry few XP), you've got to have downtime (which requires GM involvement) and you've got to blow some XP.
All that for an item at *half price?*
Ten levels later, you'll gladly pay every gold piece you ever saved to be able to trade those darn Crafting feats in for something else...