Scaled Nightmare & Stormwind Champion interaction

No reason to concede before you draw, you might get a lucky break, but people should concede more often.

Just play a few turns and see how it's going.

If someone has you at 1 health with a full board and you have no minions, you wouldn't feel obliged to play it out, right?

If your draw is awful and they have great board presence after a turn or two, maybe no need to play out every excruciating turn there either.

There is a middle ground between conceding instantly and holding out hope until the very last moment of every game.

Some games swing back and forth, sure, but if you're trying to win as many games as possible in a limited amount of time, the key is to develop a sense of which games are worth playing for wins, and which games are best ended as soon as possible.

1) Rush decks, as mentioned in some of the comments, can flat out kill a miracle rogue deck before it can set up its combo. Rogues don't have particularly good mass removal.

2) Lots of taunt spread out across multiple creatures. Some folks recommend divine shields as well (e.g. Sunwalker). But you don't want to blow all your mana on a single card or the rogue is just going to sap it. Look for 3-5 health minions, to avoid Backstab one-shots, and to make it card intensive for him to clear your board.

3) Well-timed secrets when you think his combo is coming soon, can stall him or cause him difficulty choosing how to navigate past them. Ice Block, Vaporize, etc... Even Counterspell can break up his combo. He won't want to attempt it until all your secrets are cleared.

Acidic swamp ooze might be useful to nuke some of his removal if he's stacking Deadly Poison on the Assassin's Blade. Depends on your deck.

Edit (update):

4) Random or Area targeted spells that can take out the Auctioneer while he's Concealed are useful against this deck.