Izzet Spellementals' real threats are Hearth Elemental, Eddymurk Crab, and Sunderflock, all far above mana value 2, so Seam Rip is brought in mainly to snipe their lone small permanent, Ghost Vacuum, denying them graveyard hate before it matters rather than as removal for their payoffs. Doorkeeper Thrull is a flash flier that can block their ground elementals and dodges their cantrip-based card selection since it comes down reactively. Smaug the Magnificent and Twinmaw Stormbrood come out because they're clunky against a deck that filters efficiently and can profitably trade removal like Prismari Charm or Burst Lightning into smaller bodies while racing with evasive flyers and burn is the better plan. The manabase is left untouched since this matchup is about tempo and curve consistency, not grinding.