Now this problem may be symptomatic of other complaints about the Rogue and arguements about "Head Crack" and "Edwin VanCleef". However, I've narrowed this particular argument down to just "Conceal". This is because the other cards in this combo are the Neutral cards "Questing Adventurer" and "Gadgetzan Auctioneer".
"Questing Adventurer" - Whenever you play a card, gain +1/+1.
Common 2/2 Minion, Cost - 3 Mana
"Gadgetzan Auctioneer" - Whenever you cast a spell, draw a card.
Rare 4/4 Minion, Cost - 5 Mana
"Conceal" - Give your minions Stealth until your next turn.
Common Spell, Cost - 0 Mana
Stealth is probably the hardest obstacle to deal with in this game for the simple fact that it can't be directly targeted with a spell or silenced. You have to use spells that target at random or deal damage to all enemies. Most of the time an opponent can scale their spells against the health of a minion based on mana cost. The problem here is that the synergy of the Rogue with the low to no cost spells allows for a Stealth-ed Questing Adventurer of 4/4-7/7 as early as the end of turn 2 if you have "The Coin". Granted that's under ideal conditions. If this only happened on a fluke, I might be able to dismiss it. However, it's happening a lot. It doesn't really matter when this combo comes out. When it does, it generally scales the Adventurer out of reach of a spell or you didn't draw the spell you need to combat the stealth.
The beauty of using "Questing Adventurer" over "Edwin VanCleef" is that he can buff over the course of the game and is a common card. Whereas, VanCleef is a 1 turn Legendary pony. Generally this combo is so efficient that the Rogue spells are sufficiently pestering the opponent while quietly buffing "QA". In the games where I have seen this, the Rogue always has back to back "Conceal" and has laid down "Gadgetzan Auctioneer" to either set up the combo or on the second round to draw the cards he needs to complete it. He will also use "Shadowstep" to hide the Auctioneer if he is trying to draw his combo in the same pestering way.
If you look at the makeup of the Rogue cards, you will see that the first 8 cards are 0-1 mana spells with the next 5 being 2 mana spells.
That's amazing! The Rogue can make up over 1/4 of his deck with no cost spells! Over half his deck with 1 cost spells! Oh and btw, he can carry two 0-cost spells that make two of his 2-cost spells free.
It's kind of ridiculous!!!