The Petal was banned because the only decks it was ever used in was combo decks. Not the one Spiff spoke of; that's way too inconsistent (requires 5 nonland cards to work), but Academy, Bargain, Jar, etc.
The Jar was banned because of Memory Jar/Megrim decks that could potentially kill you turn 1, usually turn 3-5. The "discard" to "bury" solution wouldn't have solved the problem because cards in hand can't be buried or destroyed, they can only be discarded.
With Fluctuator, you make a virtually all-cycling deck, then cycle through your deck until you get Haunting Misery or Living Death and Dark Ritual, then kill them. Since you're cycling and can get whatever card you need, Fluctuator is really the only card you need to go off. It could still be done in Extended, or with No Rest for the Wicked as Y the Alien said.
Apollo