Hearthpwn

This is meant to be a more of a balanced mage deck, where it should be versatile enough to handle all the classes by including a good number of creatures in the deck.  Ultimately the finisher for this deck is either the pyroblast or chaining fireballs from the Archmage.

Possible replacements:

Sylvanas:  I think a decent 5 mana drop to replace Sylvanas in this deck would be the Ice Elemental

Archmage or Pyroblast:  You would probably want at least one or the other to close the game.  If you don't have any Pyroblast, I would replace it with either big creature cards, like the 7/5 stealth assasin.  If you don't have the Archmage, it's probably not that big of a deal, and I would replace him with another flamestrike or possibly other spells.

Bloodmage Thalnos: probably the 2/2 kobold or loot hoarder.