It’s been a quiet two weeks here on Sacred Duty, and I apologize for that. All three of us have been very busy in real life, and haven’t had much time to post. And of course, Diablo III has eaten up a lot of time as well.

The Mists of Pandaria beta hasn’t given us much to talk about anyway. We have a new version of SotR, but it’s obviously unfinished. As it stands, it gives us 3 seconds of 30% damage reduction per use, along with the new Bastion of Glory mechanic that buffs WoG. It’s an interesting design, but in and of itself that doesn’t solve the mastery problems that plagued the old design. What *should* fix them, presumably, is the new addition to our mastery. Divine Bulwark now reads:

Increases the effectiveness of your Shield of the Righteous and Bastion of Glory by 10% and increases your chance to block melee attacks by 10%.

The values should scale with mastery, though the initial mmo-champion build diff showed it scaling with 1.2% spellpower. I assume this is a mix-up in their build analysis code, and that the true scaling should be 1.2% per point of mastery, which is consistent with the tooltips and character sheet on beta. However, that’s a pretty significant nerf to block (from 2.25% to 1.2%), which has to be made up for by the bonus to Shield of the Righteous (if we ignore the Bastion of Glory effect as an emergency button rather than part of a steady-state mitigation sequence).

Which brings up another quandary: the Divine Bulwark tooltip doesn’t specify *how* it buffs Shield of the Righteous. The logical conclusion is that it increases the damage reduction (DR), and that’s the interpretation that I’ve adopted. But other players have noted that the wording is ambiguous enough that it could instead increase the duration, or even simply improve the damage of SotR.

I think that neither of those are very likely, however. A damage increase is not only completely unnecessary, but fails to address the problem that prompted the re-design: the poor performance of mastery as a survivability stat. Duration would at least be a survivability benefit, but there’s two reasons I find that unlikely. First, I think they’ll be wary of any effects that increase the duration for fear of unintentionally enabling block cap. Though in this case, that fear is unfounded, because it would take over 80 mastery to reach cap, which seems like a lot even with proc trinkets.

More importantly, duration increases end up introducing a tiered benefit system. It takes about 28 mastery to add a second to the duration. If a careful player is hitting SotR shortly before a hit, then he’s already going to get two attacks out of it. With a little bit of mastery, he’ll cover a third attack, given a 1.5-second swing timer. but then it takes another 42 mastery to cover the fourth attack. That means mastery is essentially useless until you can reach that new threshold, which is likely to be unattainable, turning mastery back into our dump stat. I’m certain that Blizzard won’t like having multiple mastery caps *or *the near-uselessness of mastery between those caps, so a duration increase is probably out.

Which just leaves our initial impression – that mastery will increase the damage reduction of SotR. But even that isn’t enough, because we have no indication whether the 1.2% is additive or multiplicative. In other words, we don’t know if we get (30%+1.2%*mastery) or 30%*(1+0.12*mastery) reduction. And we can’t even test this on beta yet, both because the tooltip doesn’t reflect changes in mastery and because initial testing suggests that the mastery scaling on the buff is even implemented yet. So at this point, all we have is more guesses and questions.

However, the Monte-Carlo simulation was easily updated to handle the new mechanics, so I did so assuming that the mastery bonus to SotR will be additive. That seems reasonable given what we expect mastery values to look like (at 20-30 mastery, we’re gaining 24%-36% mitigation for a total of 54%-66%, roughly in the ballpark of the old 75% block version of SotR). I’ve been sitting on these simulation results for a few weeks now, waiting for Blizzard to implement the mastery scaling on beta just to ensure that my assumption was correct. But since we haven’t seen any indication that it will be implemented any time soon, I’ve decided it would be better to post the results to facilitate discussion, even if we’re limited to speculation.

So, without further adieu, here are the stat weights I’ve calculated from four different runs of the simulation. See the code (or the post linked above) for more details about how the simulation operates. We’re comparing the effect of adding 600 of each rating, and the calculation is done for 10,000 minutes of combat with 10-millisecond time steps. The values are related to how much damage reduction the stat gives, so higher is better.

Stat | #1 | #2 | #3 | #4 | mean |
---|---|---|---|---|---|

Dodge/Parry | 0.8059 | 0.8681 | 0.7638 | 0.7378 | 0.7939 |

Hit | 0.4120 | 0.4220 | 0.4206 | 0.4747 | 0.4323 |

Expertise | 0.3971 | 0.4732 | 0.3662 | 0.4187 | 0.4138 |

Haste | 0.2617 | 0.3684 | 0.2541 | 0.3312 | 0.3039 |

Mastery | 0.6940 | 0.8153 | 0.6701 | 0.8166 | 0.7490 |

Even with such a long integration time, there’s still quite a bit of variance between runs. If I find some time, I may do some statistical analysis with the simulation at 10 ms to get a better quantitative sense of how much these results vary, especially for shorter time scales (for example, calculating the mean and variance for a large number of 5-minute fights rather than one long 10,000-miute fight).

But for now, we can be content to note that mastery is competitive with dodge/parry and significantly ahead of hit/exp/haste with the additive implementation. That’s a good sign, because it means this implementation fixes the “mastery as a dump stat” problem. However, we should note that the additive DR assumption is a best-case scenario. If the DR bonus is multiplicative with SotR, the effect of mastery is weaker than the additive model. There are actually several ways you could calculate it multiplicatively, including the one I proposed earlier in the post, but none of them keep up with the additive model. So it will be important to test and confirm the behavior once the mastery scaling is implemented on live, because it will make a big difference in how we value mastery.

In a later blog post, once we have some confirmation of the mechanics, we’ll talk about exactly how relevant these total-damage-reduction-based stat weights are for our gearing. Keep in mind that TDR is only one facet of tanking, and it’s rarely the most important, even if it is the metric that’s easiest to quantify.

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