As you might guess from our list of new abilities in Wrath of the Lich King, leveling as Shadow in Northrend is basically the same as leveling as Shadow in Outland. The only difference is that in Northrend, you get to be a little more reckless thanks to Dispersion. Being reckless is fun.
If you've leveled Shadow before, you probably have used the "pull way too many monsters, tab DoTs, fear, and run around screaming like a fool while they slowly die" tactic. It's tried and true, so I don't know why you wouldn't. You can level pulling only one mob at a time, but why would you? Flailing your arms around in horror is much more efficient, and Dispersion makes it even better. Shock and awe, I know! Dispersion is good!
Let's take a look at the talent spec I've been using in Wrath, shall we? Note that when you look at this, it's a talent spec I am using because it works for me. Leveling is one of those times where you can get away with your talent spec being wholly different. Pick what works for you. This spec works for me.
Some oddities you may notice in my Shadow choices:
- Blackout - I'm a big fan of Blackout while leveling. It's something I dropped almost as soon as I hit 80, but for leveling it's fantastic. PvPers may keep it, but I'm a PvE noob so I toss it out the window right away. While leveling it's good because of that reckless, multi-mob way you'll be pulling things. Those stuns are good for acting as snares while you're pushing and pulling mobs around, and mitigating some of the damage you'll be inflicting on yourself.
- Lack of Silence - I don't find Silence to be especially good while just questing around. Great in PvP, decent in dungeons, not worth the point sink for leveling compared to all of the other choices available to you.
- Lack of Shadow Affinity - This build is mostly for questing, so threat reduction is not going to make or break you at all. If you run a dungeon, the Improved Shadowform threat reduction will help you out a lot, and your group won't suffer if you need to hold back a little bit. This won't hurt you in the long run. Pick it up at 80, don't worry about it for leveling.
Now, about Dispersion. Does it suck? No. Not at all. Not a chance. Is it exciting? Also no. It fits the Shadow Priest way of leveling, though. When the cooldown is up, it lets you push your limits a little more. Whereas you might have been pulling 3 or 4 mobs at a time before, when the Dispersion cooldown is up you can push it to 5 or 6. That doesn't sound impressive by itself, but when you get yourself into a rhythm where you can do that every time Dispersion is ready, it becomes very, very nice.
Routine usually goes like this: Find a camp of mobs. Tab Vampiric Touch and Shadow Word: Pain until they reach melee. Power Word: Shield myself, finish applying DoTs if I need to, drop a Psychic Scream, and start rotating through them with other damage. Mind Blasts, Mind Flays, Shadow Word: Death to get that Spirit Tap, yadda yadda.
When you pull a lot of mobs, they'll usually chew through your shields faster than you can keep them up, and at that point the incoming damage from 5-6 mobs at a time gets painful. Dispersion is great here. It essentially makes you invincible for awhile, regenerating your health and mana. You can use it to 'hold out' for your next fear or shield cooldown.
At level 75, it gets even better. What's at level 75? Mind Sear. Mind Sear is something I would never dream of using while soloing in The Burning Crusade because pushback would make it pointless. In Wrath, the pushback changes coupled with this spell? Fantastic. Your tactic more or less stays the same. Rotate DoTs on a bunch of targets, shield yourself. When you have this spell, you want to put Vampiric Embrace on a target, then focus Mind Sear on a mob that isn't the one you put VE on so you get health returns from Mind Sear's awesome DPS. It does a LOT of damage in this situation. It might fall behind other AOEs in a raid setting, but it's great for this purpose.
You'll still lose a tick or two from pushback, but that's fine. It's still fantastic damage for this purpose. Mind Sear won't hit the mob you have targeted, which is a shame. However, it's a bit like Mind Flay on Steroids on all of your other nearby targets. I think you can see how that's beneficial to how a Shadow Priest levels. You'll need to single target down your last mob, but oh well. You pretty much mangled all of the others in no time.
That's Shadow leveling. It's essentially the same thing you've always done, but now you have permission to pull like a damned fool, because you'll probably live through it! Gameplay hasn't changed much in dungeons and raids, but soloing as a Shadow Priest has become some symphony of chaos perfected.
Don't get me wrong, I still look forward to Shadow improvements in the Wrath beta, but leveling as a Shadow Priest is still fun. Very fun. It's not all bad. The problems crop up later in the game.