Why midrange paladin?
Do you not want to fight with honor? Uther the Lightbringer would not fight with secrets! He would fight with the valor of the Knights of the Silver Hand! This deck is for those who wish to climb with honor and valor amongst the hoards of unbelievers.
Also ivory knight actually lets the deck kind of be viable again...
Wait... Ivory Knight? That's a control card!
Actually it's not necessarily. I thought it was too. But it's closer to the role that Azure Drake serves in druid decks. You can think of it kind of as a cheap Ancient of Lore that is played with Fandral Staghelm up. You get a card out of it, and a small amount of healing as a bonus. Remember that midrange paladin used to run Antique Healbot as a one-of. EDIT: I've updated the list, we now run healbot instead of vigil. This sort of keeps that role. You get +1/+1 for 1 extra mana and a bit of a variable choice of healing AND A CARD. We usually want a bit more healing than the knight provides, and we no longer run Lay on Hands, so we run two for that
Do NOT underestimate the power of discover. Discover is a way to include cards that are only good in certain matchups. Even if you sacrifice that delicious healing for getting a 1 mana card (and, spoiler, paladins have a lot of those), you can often get the 1 mana card that you really need at that time. I've used Repentance to deny Grom and patrons, Humility to truesilver down a ragnaros, Hand of Protection to trade up and keep the minion, Noble Sacrifice to protect my other minions, and much more.
Keep in mind that control mages run the poorly stated ethereal conjuror, and pretty much every warlock runs the also poorly stated dark peddler. Discover is powerful.
So we've left out some cards. Let's talk about them and why they didn't make the cut.
Knife Juggler:A staple of paladin in days past, however the nerf means we can't play it as much. A good amount of the strength of juggler was being a threat that could trade up. Now it can't trade up. Or even sideways really. It's good for zoo, and this isn't a flood deck. We run Haunted Creeper instead, which is sticky, allows us to trade up, and makes our opponent think we are a secret paladin.
Steward of Darkshire: I really like this card. It's such a cool concept, but this deck doesn't have the thing that you need to synergize with divine shield: buffs. The only buff we have is Keeper of Uldaman, which is just not good enough. Steward is much better for aggro decks.
Rallying Blade: The only divine shields we have are Shielded Minibot and Tirion Fordring. We do run Coghammer, but when you play that your weapon spot is already taken obviously. A 3/2 for three is okay, but we already have 5 weapons in the deck (6 if you count tirion, 7 if you count n'zoth). Yes this does perfectly kill keepered creatures, but that bonus isn't worth a slot in our deck.
Harrison Jones: Too unreliable against aggro and zoo.
Quartermaster: A win more card mostly. We can't count on him. Too many warriors with too much AOE that kill all of our guys. We do run justicar, but she isn't begging for much more synergy, she can really crush control matchups.
Cairne Bloodhoof: Too slow. If we wanted a sticky 6 drop that was brought back with n'zoth we'd run Piloted Sky Golem.
Lay on Hands: Too slow. By turn 8 we have other things we want to do, and we have a good heavy end for the deck. If we wanted to heal we'd need it before turn 8, and we run heavier cards to need them less. Plus we push the button a lot. We run
I will assume you have all the cards you need that are common or rare. I will only talk about epic and legendary cards.
Coghammer: You might want to try Rallying Blade, the card isn't terrible and it does get value in the early game. The main purpose of Coghammer is to slow down aggro and hold them off until your bigger cards can beat their smaller ones. Rallying Blade does the same thing.
Justicar Trueheart: She's not strictly necessary, I just run her because I really like her, and she really helps vs. control. You can replace her with Loatheb, Blessing of Kings, Murloc Knight, Harrison Jones, Cairne Bloodhoof or Piloted Sky Golem
Sylvanas Windrunner: She's really good for n'zoth reasons, but if you don't have her any of the replacements for justicar will do.
Dr. Boom: Same goes for Boom as for Sylvanas. If you don't have boom, maybe don't play wild though.
Tirion Fordring: This card really isn't replaceable. I'm sorry but Tirion is a must have for any paladin that isn't straight up aggro.
N'zoth, the Corruptor: Okay if you don't have this card you will want to change the deck a bit. A good portion of this deck is built around n'zoth (yes even if it does run double zombie chow). Replacing Sylvanas is more doable, and Justicar is more mandatory. Tirion is actually a bit less mandatory, but still too good to pass up.
So How do I play this deck?
This is trump's teachings on Midrange Paladin back after Blackrock Mountain was just released. You can see the tech changes we've tried.
The strategy is relatively the same as the video. Curve out exceptionally well, and overwhelm them with the sheer quality of the paladin cards. The biggest differences is that BGH is no longer something to think about much (only sees play in Reno decks now)
Things in the video that are no longer true: Control warrior runs double brawl usually and doesn't run Alexstrasza, BGH doesn't really exist so boom is much better, Keeper of Uldaman acts as a way of dealing with high health minions (Like ysera) that used to be only cleared with equality or a big board.