Excellent points Darkmalice, and I agree completely.
Defiant set will be separated from Prankster Acrobatics, as it functions mainly as an anti-Intimidate attacker. I'll slash Taunt and Substitute on both sets, as even without Prankster, Tornadus has a blistering fast base-111 speed to work with.
Crunch will be moved to OO, as the combo Acrobatics + Superpower hits pretty much everything sans Zapdos and Thundurus for neutral damage, and no physical attack can exceed the damage of STAB Acrobatics for Tornadus (resists and weaknesses excluded). Foul Play will be dropped from OO, as the targets that are viable to hit with it have low Attack stat anyway, and you'd be better off with Crunch.
Black FC: 2537-3042-2350
VGC2012 Analysis: Slowbro