Yeah I can't see this ability staying on as is, it needs some kind of per day limit (at which point, why not just increase their number of prepared spells and call it a day).
In a dungeon crawl this isn't that bad, but the second your party doesn't have some insane time pressure, the world is the wizard's oyster with this ability. Its way too good.
In a dungeon crawl this isn't that bad, but the second your party doesn't have some insane time pressure, the world is the wizard's oyster with this ability. Its way too good.