We're going to take a small break from the usual format because the Faction Champions behave, mostly, like players. They use the general abilities that their player character class tends to use, and they even use their PvP trinket in Heroic mode.
This encounter is modelled of player versus player combat, but they don't tend to do some of the nastier tricks Arena fighters might. (For example, they'll focus-fire someone in your raid, but they're not likely to pull a complex juke. Which is to say, a sudden target switch with pinpoint precision.)
So, while most people will have an idea of what each class and spec tend to do, we'll go down the list of each possible option, with a few tips about what to expect.
The Death Knights are basically a Frost DPS build. You'll be looking at the Alliance's Tyrius Duskblade or the Horde's Gorgrim Shadowcleave. (Shadowcleave was a popular DPS Arena composition, for those who dig references.)
The Death Knights tend to spam Death Coil and Frost Strike. If you've never done PvP against a Death Knight, this might be your first time experiencing the (ahem) joys of getting hit by Chains of Ice and Death Grip. You can dispel Chains, of course, but the only thing you can do about Death Grip is curse at the monitor.
The opposing factions also have Boomchickens, and they're going to be every bit as annoying to fight as they can manage. The Alliance Boomkin is Kavina Grovesong and the Horde's representative is Birana Stormhoof. Expect your raid to get trapped by periodic Cyclones, and be ready to deal with the small swarm of Treants that never seem to go away.
Melador Valestrider is the Alliance tree and the Horde bear fruit with Erin Misthoof. The resto druids are powerful healers, but they aren't very Crowd Control savvy. They won't drop Cyclones on your raid, which is one of the tools that make Arena druids so powerful. However, keep an eye out for Tranquility and be ready to interrupt it immediately.
The tree is an Elemental and can be Banished.
Alyssia Moonstalker is the Alliance hunter and Ruj'kah is the Horde hunter. They both use a Cat. You're going to find the survival hunter a huge pain in the neck during the encounter. Not only do they provide outstanding DPS, but the hunters have a wide variety of snares available to keep you from moving around easily. This encounter, like PvP, relies on a heavy amount of mobility and positioning.
The Alliance has unleashed upon the Horde their noble mage Noozle Whizzlestick, while the Horde have set forth Ginselle Blightslinger. The mage you fight is going to spend a lot of time dropping Sheeps on your raid, and seemingly flawlessly Blinking after every Frost Nova. It's a pain, especially if your raid is heavy on the melee.
The Bubble Master for the Alliance is Velanaa, while the Horde on is Liandra Suncaller. They are incredible healers, and should be killed quickly. However, you're going to need to be trigger-ready with your Shattering Throw or Mass Dispel, because they'll bubble up as soon as they get pressured.
Baelnor Lightbearer is the Alliance retribution paladin, while Malithas Brightblade is the Blood Knight. The retribution paladins are, sadly, not the biggest threats of the crew. Watch for them to blow wings (use Avenging Wrath), though -- during those moments of glory, they definitely achieve some killing power. The paladins will also use Hand of Protection on their allies, which can significantly stymie your ability to mow down the champions.
The fact that the healing priests are specced in the Discipline tree is a good indication this is meant to mirror Arena action. Anthar Foregemender is the Alliance's chosen discipline priest and Caiphus the Stern is representing the Horde. Both wield Penance to its fullest potential, but the key ability to keep an eye out for is Mana Burn. Mana Burn is bad.
Brienna Nightfell is the Alliance shadow priest. Vivienne Blackwshiper is the Horde. They both wield the traditional shadow priest powers, like Psychic Scream. However, in addition, the enemy shadow priest will drop Silence on your raid, which can significantly slow down your casters.
Irieth Shadowstep is the cleverly named Alliance rogue, and Maz'dinah ganks for the Horde. The rogue enemy is a big fan of using Shadowstep to teleport away from the people attacking it, right behind the person the rogue's trying to kill. For that reason, it's probably best to let your melee be free-range DPS, while keeping your ranged DPS on the rogue.
Shaabad is the Alliance shaman and Broln Stouthorn is Horde. Their most significant power is Bloodlust, which will vastly increase the champions' ability to mow through your raid. If you've got the chance to kill the enhancement shaman before that hits, do so. Once it's used, however, the enhancement shaman will spend time interrupting casters. But that's about it.
The last of the healers in this list, the restoration shaman can be a nightmare. Saamul is Alliance and Thrakgar is Horde. Again, these guys can throw down Bloodlust. Even more importantly, they have an array of crowd control and healing that will keep their allies strong.
Serissa Grimdabbler is the Alliance warlock, and Harkzog rocks out for the Horde. They'll work Fear for every inch of its worth, but otherwise do a wide array of damaging attacks. They'll DoT the heck out of your raid, and occasionally do an AE Hellfire. Don't stand in fire.
Arms warriors have always been notable in PvP for their well-known Mortal Strike ability. Shocuul spams Mortal Strike on behalf of the Alliance, and Narrhok Steelbreaker busts out Bladestorm for the Horde. If you can keep the arms warrior snared and out of range, you won't have too much trouble. But the warrior will still Charge to close the distance.
On the next page: Putting it together