(11/23): After quite a bit of testing in climbing the ladder, I am 38-16 overall with mill rogue, including various card swaps, but my most recent version, which cut both ritualists for 1 evasion and 1 minstrel, is now 15-4, performing quite a bit better than previous versions, so I am editing the list to be my current version of the deck. MILL IS BACK.
(11/25): Swapped a backstab for an additional evasion. Hard to say exactly which is better, but Evasion feels much more powerful when it works since it can stall the whole board, so I think it is probably better. Also testing out some tech cards like eater of secrets and fan of knives, but haven't had great results with them,
(11/28): Reached Diamond 5 today, having climbed without bonus from last month. Total record across all versions of this deck is 87-42. Cut 1 prize vendor and 1 antique healbot for 2 glacial shards. having 2 healbots is a bit clunky and glacial shards are a nice way to stop some damage from high attack minions. The prize vendor slot is somewhat flexible, but I find that the cycle from prize vendor can be just enough to find you the card you need, especially since you can double it with valeera or brann if you need to. Other potential options are another backstab, a K'thir ritualist, or zilliax, but with the testing I've had so far, 1 prize vendor is quite good.
(11/30): After Diamond 5, I ran into a lot more high pressure decks (as expected), so I have been trying out ways to deal with higher pressure, and I found that cutting prize vendor for secret passage helped a bit, since you don't give your opponent an extra resource and you may find the card you need to stall another turn. The only downside about secret passage is that you have to be very careful not to draw too many cards or else you will start deleting your existing hand and mill a card on your next turn. You can use secret passage also to get another shadow when you are valeera the hollow, but I haven't found that aspect to be particularly useful.
(12/21): It's been a while, and haven't had much opportunity to play this month, but in the time that I have been able to test, I noticed more aggro, so I cut minstrel and coins for 2 prize vendors and another backstab to have some more early game presence. Not sure it's a lot better, but seems to be slightly better. Will also be testing some other stall cards like doomsayer and taunt minions to see if they make any difference. Also created my alternate mill rogue deck with n'zoth today to try out.
(12/30): I made a breakthrough in how to beat most of the meta! I am averaging about 70% WR, and the only decks I've really been unfavored against are Soul DH and secret mage, but even those are very winnable with decent draw. I was starting to struggle with how much token and aggro decks were showing up in diamond, but I tried something new since yesterday and was able to climb 5 diamond ranks pretty easily! I added doomsayers and depth charges instead of backstabs and glacial shards. There are too many board flood decks, so I was finding that the single target nature of backstab and shard wasn't good enough. Not only that, but the amount of extra stall these provide can be insane since you can much more easily stall into dk valeera. I also took out a prize vendor and put in zilliax. The extra heal has been nice, it can be magnetized on to healbot to deal with a big minion, the taunt can help stall against big minions, but it also helps against weapon based decks like kingsbane rogue.
(1/2): Switched Zilliax back for another prize vendor. I find the extra draw consistency to be a bit more needed than the extra heal and board control. I think there are enough stall cards that you don't need heal, you just need to be able to draw enough to get to them. Also speeds up the opponent's draw so that you can finish the game sooner
(1/21): Major Update: Armor vendor pushed this deck to the next level! No longer do you not have enough health against face decks like secret mage. I believe this could be enough to make mill rogue tier 1. Cut the depth charges and a doomsayer in favor of armor vendors and a coin, and flik for murloc tastyfin
(2/27): GUIDE IS UPDATED. It's been a while, but after the meta shift from Darkmoon races, I wanted to be sure the deck was set before updating the guide and list again. Made several cuts and replacements, mostly based on how effective they were in the meta. Glacial shards are great for beating kingsbane rogue, flik is great for beating odd paladin and darkglare warlock, and brain freeze is generally as good as sap or better for minions that you don't want to bounce back to hand. It also gives you a way to kill your tastyfin if you are worried about silence, sap, or not having something to trade into. Cards like doomsayer and antique healbot turned out to be too slow and not affective enough at stalling, though certainly cards to consider in the future. The same can be said for counterfeit coin, as it's a great way to fill the deck if you would like to ramp, but it can also leave you resource starved in some cases. *Note: These changes were made based on what I was facing in the top 500 legend meta.
Cloak of Shadows is a great addition to mill rogue in wild and can stall out the game long enough to survive into the later turns where you can make powerful Vanish plays. Mill rogue lost most of it's viability recently because Doomsayer is not really a good enough way to stall, and Preparation nerf making Vanish come out a turn later made it nearly impossible to keep up. Cloak buys a turn, similarly to Doomsayer, but it also stops nearly all face damage, which Doomsayer cannot do, which is why it fell off in mill rogue deck.
I have created an alternate mill rogue deck with N'zoth as well which can be found here: Cloaked Millzoth Rogue - Hearthstone Decks (hearthpwn.com)
Feel free to try both and let me know what you think!
If you are new to mill rogue or would like to learn how to increase your win rate with this deck, I will do my best to give some advice in this section about when to use cards, how you should play different in different matchups, and some general tips for important combos.
Murlocs are your friends.
If you are wondering what cards to keep in mulligan, it is almost always a good idea to keep coldlight oracle and prize vendor as well as mulligan all of your cards if you don't have one. There are exceptions, but I will explain those later.
You need to be very careful with how and when you use coldlight oracle. It can win you the game if you play it correctly, but can also lose you the game if you play it at the wrong time. I will also explain how and when to use coldlight in various match-ups.
When you are looking for mulligans, you generally look for Coldlight Oracle, but there several pairs of cards which are also good to keep in a mulligan
While mill is not great against aggro, it still has a chance if you draw well in the early game, so it is very important to the mulligan for aggro against these classes: Demon Hunter, Warrior, Paladin, Mage, Druid, and Hunter. While the other classes can certainly play aggro, I haven't found it to be the dominant archetype when facing those decks, so it's up to you what you want to mulligan for aggro or not. Generally, if in doubt, mulligan for aggro counters so you can be ready if necessary.
Most importatant keeps:
Preparation, Evasion, Cloak of Shadows, Glacial Shard, Prize Vendor, Armor Vendor, Brain Freeze, sometimes Sap (If the deck you are facing applies pressure through buffing minions), and sometimes Shadowstep (If you plan on bouncing Armor Vendor or Glacial Shard back to hand)
Mill traditionally has been a counter to control and combo decks, and this certainly hasn't changed.
Most important keeps:
Coldlight Oracle, Shadowstep, Lab Recruiter/ Togwaggle's Scheme (don't keep both), Brann Bronzebeard (only if you already have coldlight in hand), Swindle, Murloc Tastyfin (if you don't have any other murlocs), and Prize Vendor.
The Aggro Matchup:
Navigating this matchup can be difficult, but not impossible. so Hopefully these tips can help you improve your winrate against aggro decks.
1. Be very careful with your use of stall cards, especially against decks which run a lot of burn. If you use them too early, they may not be stopping enough damage to win you the game. You also don't want to be overly conservative with stalls to the point where you get burned to death. However, if you think you can tank damage for a turn, then do so, and spend your turn drawing cards with swindle, coldlight, etc.
2. Be careful not to shuffle your coldlights too early. Too many coldlights in hand early on can cost you the game. It is okay to play your first coldlight "naked" without a bounce or shuffle, because sometimes you will just want to get to your stall cards faster and spend your early turns surviving.
3. The most important factor against aggro is knowing what cards are in your opponent's deck, which is not too hard to figure out if you are playing against a meta deck. For example, if you are against an odd paladin, you know they run a buff card at 5 mana, so you might want to play a stall card preemptively at 4 or 5 mana (depending on who goes first) so that their buff does minimal damage. It also is very helpful to know how much burn is left in their deck, how likely it is that they have drawn it, and compare it to how much available mana they have and how much health you have. If you are at 12 health against a secret mage, for example, Even if they have no minions on board, if they have 2 fireballs/Prince's left in their deck and 8-9 mana, you will probably want to use evasion or cloak of shadows.
4. Coldlight is not your only win condition. In cases where the opponent runs a lot of burn, it can be helpful to bounce or shuffle armor vendor so that you stay out of lethal range, lacial shards to stop them from hitting you with weapons, or flik to beat odd paladin/jade druid. Once you are Valeera the Hollow, you will be able to gain a ton of armor each turn alongside vanishes and just be able to stall out the opponent long enough until they run out of ways to deal damage.
5. Be very careful when playing around secrets. Unfortunately for this deck, secret mage is still pretty relevant in the meta, but it is still quite winnable if you play around secrets and burn well and have a bit of luck.
6. Practice. These matchups will be discouraging at first, especially if you are unfamiliar with the wild meta, but they will get a easier over time. A lot of planning is needed, and practice will help you figure out how to make those plans more easily
7. Don't be afraid to adjust the deck a little if you are facing a lot of aggro matchups. Some cards definitely depend on the meta and can be adjusted to tech against certain more prevalent matchups. It might be hard to know what to cut at first, but with practice, you'll know what cards are the most effective in the matchups you are building around.
The Control/Combo Matchup:
This deck is made to kill these decks, but you still need to be careful not to play cards too soon.
1. Coldlights Oracles are vital to success in these matchups, so if you believe you are against control or combo, like priest, then it is safe to mulligan your entire hand searching for coldlight.
2. Never play coldlight without a way to bounce it or shuffle more into your deck, unless you already have another one or tastyfin in hand. The only exception to this is brann + coldlight, or if you are desperate to survive.
3. If you are against a deck which runs mill cards or shuffle cards (like tickatus, coldlight oracles, naturalizes, espionage, archbishop, etc.), Be sure to save lab recruiter and at least 1 coldlight in hand until you can shuffle more lab recruiters into your deck, either with scheme, your other lab recruiter, or valeera's hero power. This will allow you to go infinite.
4. Do not be afraid to tank damage for a few turns. These decks run little to no burn a lot of the time, so sometimes the best move is just to pass and let their minion(s) hit you in the face, and let them commit more to the board before vanishing and milling a ton of their deck.
5. Take advantage of having them draw their own cards. It can sometimes be helpful to wait until they have 9 cards in hand to play your coldlight combo, since they will likely be drawing a lot themselves or generating cards.
6. Sap's primary purpose here is to burn more cards, so if their hand is nearly full, sap and then play coldlight for more cards milled. The only real exceptions to this are very disruptive battlecries or effects like loatheb, tickatus, and cloud prince, as well as 0 cost minions like giants, in which you'd only want to send them back to hand if their hand is already full, so it would be better to freeze them with Brain freeze or glacial shards if you can't fill their hand.
7. Flik can also win you the game a lot of the time in the right matchups. If you can play flik to get rid of a key card, like shudderwock or jades golems, be sure to save it for that purpose. Against Jade driuid and odd paladin, Flik is actually your main win condition, so after shuffling coldlight once, you'll want to shuffle her into your deck instead of coldlight.
There's plenty more that could be said about how to properly pilot the deck across various matchups, but I hope that this guide was helpful enough to get you started and able to practice to figure it out on your own! Let me know if you have any more questions about specific situations or card options.