Awww, come on...you all know, deep down, you want to see something like Power Matrix again.
A global effect would be cool. Then again, an activated ability akin to Mirari would be nice also.
Here are a few ideas, just rough draft brainstorms:
-Players cannot declare an attack phase unless they discard their hand.
-When THIS comes into play, draw a card, then discard a card. Each player draws an additional card during their draw step, then discards a card.
-Whenever a creature deals combat damage to you, you may pay 2, if you do, draw a card. Use this ability only once per creature.
-During your upkeep, put a Psychic counter on THIS. During any upkeep, any player may pay 4 to remove a Psychic counter on THIS. During each player's draw step, that player draws a card and loses 1 life for each Psychic counter on THIS.