Hearthpwn

Hello Havlen

I honestly think both are key:

a doomsayer can almost gurantee a full board clear at  5 mana with frost nova combo or turn 8 with blizzard . 

Iceblock can give you the turns you need to spend the mana to finish your combo. (For example, Use Iceblock, Fireball, iCeblast, icelance) and you'll be safe from any dmg from your enemy because of the iceblock (unless you are fatigued) then next turn pyroblast or something like that to finish him off.