The card begs the oft-asked question, In the absence of an objective rule structure, do we all become Squee? The most obvious use of the card is to strengthen the waning popularity and power of U/R Storm in Modern (for a good list pre-Faithless Looting, see the list that I cited in my last article)
Play Booster display boxes, however, will have 36 boosters like Draft Booster displays did (as two boxes are exactly enough for three 8-player drafts)
At the start of combat on your turn, you get to give another creature haste and myriad
Blue's undisputedly the best at card draw, and if Green wants to draw cards they have to jump through a hoop, like dealing combat damage with a creature
Where this card will undoubtedly be great, however, is as a Grixis flashback commander