Versatility and Its Relative Value
As you are probably aware, versatility is one of the new stats in Warlords of Draenor. It increases damage and healing and decreases damage taken, but for the purposes of this blog post we are only concerned with the damage increase. Blizzard has stated that they don't want these components to be strong enough to be the same as other stats, because the secondary effects would then just make it the preferred stat. However, they also don't want to make it so weak that the gear it's own is worthless, so it's a bit of a fine line to balance. Where it stands right now is that 1% versatility requires 130 combat rating, while crit and haste require 110 and 100 respectively.
I've been working on a hunter web app which isn't quite polished yet, but it's getting close enough that I might be able to get some reasonable idea of how good each stat is. I think we can expect each specialization to have very different ideas about the value of each stat, and in some cases perhaps even certain talents (haste may be a big concern if you take Focusing Shot, if focus capping remains an issue). But for one test I decided to use a human Survival hunter with Fervor, A Murder of Crows, Powershot, and Focusing Shot. For each stat, I increased it in intervals of 10 up to a max of 50, while keeping all other stats static.
Sorry, I don't have the actual chart to show here, but I do want to talk about some general concepts from it. Most of the results were about what I expected: crit, versatility, mastery, and agility were all straight, linear lines with slightly different slopes (well, agility's slope was much steeper). Haste and Multistrike looked good, but were all over the place - small changes in one of these stats would result in rotation changes that ended up in some big jumps after a 360 test. (Keep in mind that multistrikes have a special behavior for survival and will result in a rotation change due to more Lock and Load procs). These are partly statistical noise and partly a sign that I might want adjust the conditionals employed in my rotation sim to be more efficient. But what surprised me was the order of my linearly scaling stats: versatility > crit > mastery. Crit being slightly ahead of mastery makes sense since everything in my rotation can crit but a couple things do not benefit from my mastery (pets, powershot, focusing shot, murder of crows) despite them having the same cost. But why is versatility performing better than crit even though it is more expensive?
My first thought was that there was a bug in my app. After breaking down each formula trying to figure out which part I got wrong, I realized that nothing was wrong, and the explanation for versatility's performance had to do with my starting values and the relationship between crit and versatility. You could remove all of the other common factors in the calculation and be left just looking at the difference between crit*versa. Basically, crit and versatility fully interact with each other, such that raising the value of one increases the relative value of the other. Assuming they cost the same (they don't quite, but I'll address that later) you'd want them to be about equal to maximize the product. A quick example: Imagine you have two values, 1.5 and 1.1. You can increase one of them by 0.1. The answer is simple: 1.5*1.2 > 1.6*1.1. Well in my calculations I was just using a set of gear on the beta that had only 77 versatility (plus 100 from being human) but 1052 crit rating. Since crit is more cost effective than versatility by a ratio 110:130 what I'd really want is for the ratio of my final crit and versatility to be about 13:11. Mastery is about the same, although not quite due to it not working on all damage.
It is important to note a couple things here. First of all, switching all of my crit rating to versatility left me with 17% crit (against a level 103 target) and about 12.4% versatility (so still a bit below our golden ratio) but only improved my DPS by 0.4%. That's pretty small, and that's with a drastic adjustment of stats that isn't actually possible to do. It also looks like multistrike and haste are the better stats so I'll probably want to go after gear with those stats and not really worry about whether it's other secondary stat is crit or versatility or mastery. So since versatility isn't the primary stat we are going for, it could still be acceptable to Blizzard that it is better than some secondary stats. But if I have the choice between multistrike/crit or multistrike/versa for my SV gear, I'm taking the one with versatility at the moment!