Resto Tier 1 - Currently, there isn't a lot of debate about this tier of the tree, but that may change at some point. Improved Mark of the Wild and Furor are currently favored because they provide a little extra DPS and regen. However, it is really pretty minor. In a heavy damage situation pushback resistance can be a big DPS boost. Since most guilds have Imp MotW covered by a Resto or Feral Druid, don't be surprised if you see many Moonkin taking points out of Imp MotW or Furor to put a few in Nature's Focus, if the situation calls for it.This prompted the following comment from a reader:
Imp MotW is not what I would call a debatable talent. 2% stats wins over pushback in a PvE setting.For the record, I want to say that I don't think Pushback Resistance issue in the current PvE content. That is the exact reason why I didn't included Nature's Focus as a part of my core build in my Moonkin Basics post. However, he was so dismissive with regards to the value of Pushback Resistance that I fell it is necessary to address the topic more formally. In the following post I hope to show you why you may want to pay attention to Pushback Resistance in the future.
How Spell Pushback Works
You will experience Spell Pushback if you take damage while you are casting a spell. However, how it affects that spell depends on the spell type. For a Channelled spell like Hurricane, tanking damage while channelling the spell reduce the spell's duration by 20%. For a spell with a cast time like Starfire, taking damage while casting will increase the cast time by 0.5 seconds. The good news is for both types of spell, only the first two hits will incur spell push back. So, spell pushback can only reduce your channelled spell duration by 40% total, or increase your cast time by a maximum of 1.0 seconds.
Unfortunately, the only way to reduce spell pushback is with the use of talents and buffs. I did some testing over the weekend and proved to myself that Haste has absolutely no impact on the cast time added by spell pushback. Fortunately, Moonkin have several tools available to them to combat spell pushback.
Celestial Focus - When fully stacked CF will reduce the Pushback on your Starfire and Hurricane by 70%.
Nature's Focus - When fully stacked NF will reduce the Pushback on your Wrath and most of your healing spells by 70%.
Barkskin - Your push back is reduced by 100% for all spells while Barkskin is active.
Owlkin Frenzy - Your push back is reduced by 100% for all spells while OF is active.
Concentration Aura - This is from a paladin. It will give you 35% resistance to pushback if you are in range of the pally.
These buffs stack additively. So, having Concentration Aura with Nature's Focus and Celestial Focus gives you 100% resistance to spell push back.
The Math of Spell Pushback:
For simplicity's sake lets make a couple of stipulations. Lets say that the average Starfire hits for 10,000 damage and takes 2.0 seconds to cast. Lets also say that the average Wrath hits for 5,000 damage and takes 1.0 seconds to cast. I know that these are not percice numbers but more accurate numbers are not needed to show the impact of spell push back.
So, using these numbers, both spells have 5,000 DPS if they do not suffer any spell pushback. With the first hit, Starfire's DPS will drop to 4,000 DPS (10,000/(2+0.5)), and Wrath's DPS will drop to 3,333 DPS (5,000/(1+0.5)).
As you can see, taking a hit will have a significant impact on your DPS. On top of that, a spell like Wrath that has a shorter cast time has an even larger drop in DPS due to spell pushback, because the amount added is not relative to the cast time. Of course, Wrath is more likely to avoid spell pushback due to it's shorter cast time. That will reduce the impact of spell pushback some, but it will still have a greater impact then Starfire.
So, what happens if we put a point in Celestial Focus or Nature's Focus? The DPS of Starfire will rise to 4,193 (10,000/(2+(0.5*(1-0.23)))), and the DPS of Wrath will rise to 3,610 (5,000/(1+(0.5*(1-0.23)))). For Starfire this is a 4.83% DPS increase and a 8.30% DPS increase for Wrath. The second and third point have even larger marginal impacts on your DPS. However, this benefit is only realized if you take damage.
Why Spell Pushback is Important
Some of you may be thinking: "I realize that pushback has an impact, but I don't get hit enough in raid for it to have a big impact."
As I said before, I agree that Pushback Resistance isn't hugely necessary in the current raid content. Naxx and Ulduar don't have a lot of unavoidable raid wide damage. ToC has a little bit more but it really isn't enough for it to be a big issue yet. On top of that Celestial Focus is a core talent of any moonkin due to the Haste it provides. Therefore, we are currently pretty well covered as it is. The question is, what type of damage will we see in ICC?
If you take a look back at Black temple and Sunwell, you will see that frequent damage was more of the norm then infrequent damage. In some of the fights like Bloodboil we were getting hit with damage every 2 seconds. If Wrath is 40% of your damage, and 50% of your wraths are getting delayed due to push back, each of those points in Nature's focus will now increase your DPS by 1.66% to 2.09%.
We are only just now getting our first looks at the bosses of ICC, and we don't know what they will look like in hard mode. As such, I can't make any definite statements about Pushback resistance being necessary in ICC or not. However, don't be surprised if you start to see a lot of high level moonkin starting to make the switch. The reason is because Pushback can have a huge negative impact on your DPS if there is enough damage being thrown around.