The ShiftstonedEternal Power Calculator is a deck-building tool that visualizes your odds of drawing enough Influence and Power based specifically on the cards found in your deck.
I wanted to fill in a card (just 1x because that's all I had left) that worked against a broader range of aggro/mid potential. Some of the tougher aggro targets (and things like Feln Bloodcaster/Steward of the Past) are easily stopped by Suffocate. Annihilate is a good card, but I had too many other options in the 2 power slot.
Depending upon your opponent, you can slim down on Permafrost (especially against decks w/ Endurance, i.e. Tavrod) as well as Lightning Storm. Decks that are more control-oriented tend to have fewer creatures/early game options so there can be a reduction in anti-aggro cards.
Hey! I wanted the mainboard to be geared towards aggro match-ups so I don't know if I'd change much. If Yetipult isn't doing much for you, subbing in more Suffocates can work. The sideboard was reserved for playing versus control.