So I hit level 40 last night and finally picked up the most iconic spell of a shadowpriest: Shadowform!
Shadowform now has one of the largest descriptions I've ever seen for a single spell and I'm going to take a look at what it means exactly.
That description can seem a little overwhelming to a new shadowpriest and although everyone understands that it is good, not everyone can fully explain why. Also take a look at the mana cost to put Shadowform up, its not cheap so always remember that when dropping Shadowform for a quick heal or two. However the mana cost is actually a lot less than it used to be before patch 3.3 and should not be overlooked when you think providing some off heals may be useful.
Damage Increase / Damage Reduction
Ok the first part of the descrption is probably the most straightforward. Having Shadowform increases all shadow damage that you do by 15% and reduces all the damage you will take by 15%. Nice and easy, this spell will make you hit harder and take more hits.
All threat generated is reduced by 30%. As I mentioned before, being a shadowpriest means you will put out some pretty constant damage as well as group healing, which means that you may attract a little more attention from your enemies than you would like. A flat 30% threat reduction will help compensate this and let you breathe a little easier when you start melting faces in PvE.
Cannot cast Holy spells
This is the biggest disadvantage to a priest using Shadowform. You cannot use any holy spells apart from curse disease/abolish disease. This means that if you want to heal you will need to drop Shadowform. Dropping Shadowform means that you will lose all the advantage it provides until you recast it. When you recast Shadowform you will be using a fair amount of mana and wasting a Global Cooldown. So always assess whether dropping Shadowform is essential or not. However don't be afraid to drop it when needed as you can often save your own life or a member in your party / raid. When playing in PvP you will need to drop Shadowform more often depending on what situation you are presented with.
Increased DoT crits
This part of shadowform is awesome on so many levels! Allowing your DoT spells to crit for 100% increased damage will vastly improve your DPS if you have some decent crit rating. Remember this increased crit damage will only take place when the player has Shadowform up and you really will see some awesome damage. It is also a god send in PvP when you see your DoTs crit just as you prepare a Mind Blast.
Haste now helps Devouring Plague / Vampiric Touch
This is a rather new addition to Shadowform and it is the reason that many Shadowpriests now love haste. By stacking haste you can make your DP/VT spells do the same amount of damage in a shorter amount of time and thus increase your DPS drastically. Haste is a great stat to have and it provides all sorts of benefits. One of these being the time it takes for your Global Cooldown is reduced and this will let you use your spells and abilities that much faster. Haste can be extremely useful once you get the balance right with your other stats and I will be looking at this at a later time.
So as you may have noticed, I love Shadowform and this will make my leveling process a little easier from now on. Also don't forget, Shadowform makes everything look bad-ass.