As long as you keep the flavor of the original story in mind - yes, you get wishes, but the damned thing *will* twist whatever you wish for into something horrible that you'll have to deal with...
And, the "overly clever" types who spend days working out highly legalisticaly termed conditions and clarifications etc.?
As a DM, for items like this, I always made the wish to be the first sentence, break, comma, whatever..
Player: "I wish for unending wealth, that -"
DM Voice in Player head: "Done!"
Player: "But I wasn't finished! That wasn't what I wanted!!" <angst> <woe><misery>
DM Voice in Player head?"BWWHHAA HA HA HA HA! Foolish Mortal - trifling with powers beyond your ken! Bwwwaaah! Ha Ha HA HAAA!"
Or sometimes it wouldn't work at all with the run-on blather - if I was feeling extra nice or if the player was too shiny-new.
IMAO - It's pretty much got to be a dark aspected item.
Powerful - Who's to say that it doesn't have a personality and or preferences of it's own, complete with resentments and hatreds.
Think a wish-granting, Necro-Bob flavored item!
These are things that are system independent - once you have the concept of what it's going to do, you can tailor appropriately...