This is mostly just to help me organize my thoughts on the matter.
Increases the damage done by your Starfire and Wrath spells by 4%.
The major advantage of this bonus is that it is reliable - it has no RNG component at all. It also doesn't have any major disadvantages, but it is important to note that the talent is additive and not multiplicative. For example, during Solar Eclipse 4t9 is actually only a 2.66% increase to Wrath damage. This makes it relatively weaker then you might expect at first glance.
Math generally shows 4t9 to be worth slightly less than 3% dps.
When you gain Clearcasting from your Omen of Clarity talent, you deal 15% additional Nature and Arcane damage for 6 sec.
This bonus has a couple of interesting factors to it:
- If it works like other similar buffs, then the benefit will last the entire duration of a DoT. A moonfire, IS or Starfall that you cast during a 2t10 proc should tick for 15% more the entire duration.
- You can gain Omen of Clarity automatically by casting Gift of the Wild. This means that if you need to, you can use 2t10 to gain on-demand burst dps. Since balance druids generally lack this, it might be valuable to explore (for example, imagine if you were having trouble on Marrowgar hard mode killing bone spikes - it would be very possible to hit gotw just before the cast finishes and get that little bit of extra burst for ~5 seconds). Keep in mind that for overall sustained dps, casting gotw is going to be a loss unless you can do it while you're moving. This isn't something you add to your rotation every six seconds - but that doesn't mean you should ignore it either, and hitting it right before the fight starts (as another form of pre-potting) may also be valuable.
- AOE - Omen of Clarity procs a lot when you're chaining Hurricanes. 2t10 should be a significant boost in damage on any fight with a significant AOE component.
- RNG, RNG, RNG. Omen of Clarity is a relatively low proc chance (6%), and on average you will see around 2.5 procs per minute on a single-target fight. But there can be a lot of variance in that number - the odds of going an entire minute with zero procs is roughly 8%, which is high enough to occur relatively often. Other fights might yield you 4-5 procs per minute, it's all up to the dice gods.
- Six-second duration - spell damage is calculated when the spell cast finishes, not when it starts. To get the 2t10 bonus you have to finish the spell cast within the buff duration, which means that calculating uptime on a six second duration is inaccurate - you will generally only get 5 to 5.5 seconds of useful buff time out of each proc.
- Set itemization - separate from the set bonuses themselves. 2t10 allows me to drop two items with spirit. Even with the marginalization of haste past the soft cap, it is still very much superior to spirit.
- Item lvl - I still have mostly 245 t9. Going to t10 gets me 251/264 items, which is a very nice stat gain.
- Experience. Using 2t10 optimally means paying attention to the procs. I have 1.5 seconds left on a 2t10 proc during Lunar Eclipse - do I cast a starfire (which will not benefit) or do I put up Insect Swarm, which will? Since I will definitely have this set bonus at some point, the earlier I start watching it and incorporating it into my decision tree the better off I will be later in hard modes, when paying attention to dps will take a second seat to fight execution.