Post by visas
Ok, so I finally gave in and decided to try testing out dual wield vs 2hander DPS on the beta realms.
Now, talent builds used for reference - both builds were tested at level 64 (my current level on the realms). My 2hander was hellboar carving blade, while my DW setup was using two footman's swords.
Note: The footman's swords are exceptionally better in quality than the 2hander I was using, which is very likely part of the result.
This was my 2hander unholy build:
http://wotlk.wowhead.com/?talent=jbZZbgh0tfogtoocoutAnd the dual-wielding build:
http://wotlk.wowhead.com/?talent=jfMhVZGMcx0xZbGh0xfResults:
-the 2hander does noticably more damage on attacks, but at a much slower rate. With the 2handed build my blood strikes generally crit for 900-1000 damage average, with 3 diseases (frostfever, blood plague, and ebon plague) on the target. With the dual wield spec, my blood strikes crit for around 600 - but they crit a hell of a lot more and it seemed to be a much 'faster' build damage-wise.
-In order to put together a viable dual wielding spec, you have to get certain talents in all 3 trees. This makes it difficult to get any of the higher end talents or 'cool' abilities you get later on in the other trees - things like hysteria, frost strike, unholy blight, anti-magic zone, etc. The biggest impact this has is that a dual-wielder, if specced to maximize the effect of his chosen weapons, will not be able to bring the utility buffs to a raid that other deathknights are able to bring.
-With the dual wield build, I'd have been destroyed by any multi-mob encounters (anything over 3-4 mobs) - whereas the unholy build could easily handle 10+ targets due to stacked aoe with death and decay, corpse explosion, and unholy blight (plus wandering plague and pestilence, if I had them working at the moment).
There are also obvious theorycrafting implications to dual-wielding while tanking - no matter which way you slice it, a DW tank WILL take more damage than a 2hander tank unless expertise capped - and I dont think it will be in any way easy to hit the expertise cap at 80, even with the +12 expertise blood talent and human/orc racials.
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Conclusion:
Dual wielding is a perfectly viable alternative to using a 2-hander while leveling up, and it's even fun to play (though, in my opinion, doesnt fit the death knight 'image' at all). However, dual wielding will not be an effective method of tanking at 80, and it will not be desirable for DPS death knights in raids due to the raid utility buffs you're forced to give up. You could probably manage to DPS with dual wielding all through 5 mans, but dont expect to get a raid spot using two weapons.
EDIT:
one more thing to note, when I was dual wielding I was in frost presence (no 15% damage bonus) - I didnt realize this until after I had switched my spec back. However, I think having an equivalent-quality 2handed weapon would have made up for the damage difference, so that has little impact on the damage output itself.