Quote from BloodyWednesday »Except Biorythm on a stick has a tap ability and condition to activate him. Griselbrand works exactly the same as bargain except with a body + lifelink.
Would it have been nice if they had waited a bit more? Sure, but why would they. If they released Worldfire on a stick (ie some creature with some stats and “sacrifice ~: do worldfires effect”) it would likely be banned as soon as the next rotation hit.
You forgot he can also sit in the command zone