Gruul Goblins fields an army of 1- and 2-toughness bodies (Goblin Lackey, Mogg Fanatic, Matron, Ringleader, King, and Siege-Gang's tokens), making Pyroclasm a near-blowout that clears their board for 2 mana. Blue Elemental Blast answers a key red permanent like Goblin Warchief while countering key red spells. Daze is weak here since it costs you tempo against a deck that doesn't care about card advantage, and Mana Leak is too easily played around once they have Rishadan Port mana up, so both come out. Keep Wild Mongrel and Basking Rootwalla in to race and use Survival of the Fittest to find Gilded Drake against their bigger threats like Siege-Gang Commander.