ED: This post was written prior to 6.0 and is based on beta numbers. Some of the information has changed.
As soon as I started looking at our stats at level 100 in WoD, I realised that the Multistrike vs Crit question was going to be pretty interesting. On the face of it, the two are actually very similar. Multistrike’s mechanism is very similar to that of Crit, with 2 chances of doing a set % of bonus damage, rather than a single chance of doing a set % of bonus damage. Below, I’m going to compare Multistrike and Crit, so that you can see not only which is better, but how they impact one another.
Below, I’m going to use the term “simple healing” to denote that I’m ignoring real life factors that we have to deal with, like when crits are partially wasted because they would take the target beyond full HP. We are talking pure numbers in a scenario where all healing is beneficial.
Item Level Budgetisation
At this stage, the item level budget is the equal – variations of the same item might have 40 crit or 40 multistrike.
At the base level, 112 Crit rating gives 1% Crit, which is worth +1% additional simple healing overall. On the other hand, 112 Multistrike rating gives 2% Multistrike, which is worth +1.2% additional simple healing overall.
There is one factor to consider, which is that Crit increases the effectiveness of Multistrike. This only goes one way though – Multistrike doesn’t increase the effectiveness of Crit. The reason is that Multistrike is flat damage – if the original hit wasn’t a crit, the Multistrike(s) won’t be a crit – it’s just 30% of the damage.
The question then becomes, does Crit overtake Multistrike at a realistically attainable level of Crit?
The priority of Multistrike vs Crit basically comes down to:
Multistrike > Crit
The margin is pretty narrow, such that if an item is a higher iLvl but has Crit rather than Multistrike, there’s a good chance that it will still be an upgrade. If you were to keep Crit & MS ratings equal (as in, a 1:2 ratio, because the cost ratio is the inverse 2:1), there is actually a point where Crit would become a greater increase than Multistrike. This would occur at 28% Crit / 56% Multistrike. This is most likely not going to be achievable (or worthwhile with Mastery & Haste both being priorities ahead of MS).
The Math To Explain
The next section has the math on the subject. It’s not really number heavy, it just justifies what I’ve said aboce. If you aren’t interested, feel free to skip this part and trust what I say. Otherwise, please enjoy, and as always, contact me if I make an error!
Another way to look at Crit’s increased effectiveness from Multistrike is that 112 Crit rating is now worth slightly more than 1% increased healing, because points in crit not only boost your direct heals/damage, but your multistrike heals/damage also. The gain is so small per point of crit that you might be able to just remove it from any napkin math calculations you do to establish whether an item is an upgrade or not.
For example, at 5% crit (base), you actually gain +0.6% (that’s 0.006) per MS%. At 10% MS, that means your 5% crit translates to a 5.018% (0.05018) increase to healing. The key thing to realise here is that this compounds, so as your crit increases, the bonus to crit increases as your crit increases
For comparison, take a scenario where we you have 1680 rating worth of either Crit, MS or a mix to choose from.
The best option is to spend it all in MS, so that our stats look like:
Compare that to the opposite, where we’d spend it all bar what we need to get to 1% MS:
And then take the following case where you use more of a mix:
Note how increasing them evenly is a pretty minimal difference from stacking stacking MS on every slot. For reference, it looks like the first tier of epic gear (iLvl 660) generally has an secondary stat budgets of:
Chest – 294 (2 stats with 147 each)
Gloves – 220 (2 stats with 110 each)
Every piece you get in a pre-Raid set will probably have Mastery on it, most will have Haste, which leaves very little chance that you’ll get anywhere close to these levels of MS/Crit.