Replacement for Archmage Antonidas in Mech Mage

Cards to consider adding vs aggro decks:

• 1 Blizzard - I would highly recommend you put these in, due to the fact that they both freeze all your opponent's minions, AND do 2 damage to all of them, killing a large number of aggro creatures and stalling others.

• 2 Vaporize - If you're keeping the board clear of smaller minions, this'll help you take care of bigger minions if used properly.

• 1 Arcane Missiles - Can 2 for 1 against aggro rush decks, assist in taking down 2 toughness or greater minions. Cons - Based on RNG.

• 2 Mirror Image AND/OR 2 Ice Barrier AND/OR 2 Frost Nova - One of the biggest counters to an aggro deck is stalling it out, especially in a Mage deck where you can pull a turn 7 flamestrike. These 3 cards are all excellent for stalling, as Mirror Image basically prevents 2 creatures from doing damage, even charge creatures, Ice Barrier, being a secret, can cause your opponent to play abnormally, such as playing a smaller minion than they would have because they're afraid of Mirror Entity. In addition, it basically heals you 8, even if you're at full health, which is pretty solid vs an aggro deck. Frost Nova is likely the weakest at stalling an aggro deck, due to not effecting charge minions at all, but is more relevant typically late game, due to effecting all of your opponents minions out currently.

• 2 Cone of Cold - While Arcane Explosion is generally considered a bad card, Cone of Cold is relevant at times, due to the fact that those minions it doesn't kill with it's 1 damage will still be frozen for a turn, making it still a relevant card in the late game.

Cards to change out:

• 1 Gadgetzan Auctioneer -> 1 Acolyte of Pain - Gadgetzan Auctioneer isn't necessarily guaranteed to draw you a card when you play it, and is a high costing 5 drop, with not very high toughness. Alternatively, Acolyte of Pain is almost always guaranteed to draw you a card, unless silenced or straight up destroyed, and, when combined with your hero power, will be able to trade for 2 toughness or less creatures well.

• 1 Argent Squire -> 1 Mana Wyrm - Mana Wyrm is one of the best 1 drop minions in the game, very often 2 for 1's, or at the very least, trades up. Argent Squire CAN 2 for 1, but only against 1 toughness creatures. In addition, it doesn't have ANY impact late game, whereas a mana wyrm can.

Cards to consider taking out:

• 1 Sunfury Protector - While not the worst card, this is the kind of card that doesn't really do anything unless you have other cards to go with it. In this case, those other cards happen to be minions. When combined with a Chillwind Yeti, or better yet, a boulderfist ogre, it can be very powerful, but without one of those, it doesn't necessarily do much. If you still like the synergy of it with minions such as these, I would recommend replacing it with Defender of Argus, as you're almost never going to be playing Sunfury Protector before turn 5 or so anyways, and Defender of Argus is more relevant with minions such as Acolyte of Pain and Mana Wyrm

• 1 Azure Drake AND/OR 2 Boulderfist Ogres - If Aggro decks are really your only weakness, I would consider removing some of these more expensive creatures. Boulderfist Ogre is particularly useless against aggro decks, because they will just proceed to ignore your ogre, since they likely have you far lower at the point you play it than you do them, and you can only use it to kill one minion of theirs a turn.

Scenario 1:

In most cases, mulligan for your combo!

Since your deck has no Wild Pyromancer and very few early drops, I believe your best chance for taking control of the field is your Auchenai Soulpriest and Circle of Healing combination.

Grabbing control of the board against aggressive decks is key to winning when playing as the Control Priest. Therefore, this combination is so important, that you should mulligan aggressively for it.

That said, if you have a 1 and 2-drop (Northshire Cleric and Acidic Swamp Ooze) or a 2 and 3-drop in your hand in addition to the Circle of Healing, playing those will give you enough board presence early on to protect your health until you do draw your Soulpriest (or at least have enough chance to draw it as you would with a mulligan).

Scenario 2:

Mulligan Thoughtsteal. Below is an explanation why.

I am assuming that Dark Cultist or Injured Blademaster is a better turn three play than Thoughtsteal in most circumstances, so you would rather have one of those in your hand. Since you have two of each Thoughtsteal, Injured Blademaster, and Dark Cultist, you have six cards that you could draw by turn three that would be as good or better than Thoughtsteal.

• Mulligan
  • You keep 2 cards and mulligan Thoughtsteal.
  • There are 5 cards as good or better in your deck.
  • Your deck has 27 cards.
  • Chance that you draw something worse for turn three: 22 / 27
• First turn
  • You drew something worse.
  • You have three cards in your hand and you draw one.
  • There are 6 cards as good or better in your deck.
  • Your deck has 27 cards.
  • Chance that you draw something worse for turn three: 21 / 27
• Second turn
  • You drew something worse.
  • You draw another card out of your remaining 26 cards.
  • There are 6 cards as good or better in your deck.
  • Chance that you draw something worse for turn three: 20 / 26
• Third turn
  • You drew something worse.
  • You draw another card out of your remaining 25 cards.
  • There are 6 cards as good or better in your deck.
  • Chance that you draw something worse for turn three: 19 / 25

The chances of all of this happening in sequence is (22/27) * (21/27) * (20/26) * (19/25) = 37%

That means you have a 63% chance to draw a replacement Thoughtsteal or one of your Dark Cultists or Injured Blademasters by your third turn. Therefore, mulligan that Thoughtsteal!

Remember, in a control match-up, you have a very good chance to draw it again later, when it is more useful.