Also keep in mind...
Where x is the non-crit healing throughput (the healing that you would do if nothing crit).
Current Throughput =
x * (1 - Crit Rate + 1.5 * Crit Rate)
New Throughput =
x * (1 - Crit Rate + 2 * Crit Rate)
x * (0.5 * Crit Rate)
Lets say your healing throughput is 15,000 HPS and you have a 15% Crit Rate (arbitrary round numbers). This throughput is your maximum, so it includes overhealing.
15000 = x * (1 - Crit Rate + 1.5 * Crit Rate)
x = 15000 / (0.85 + 0.225) = 13,953
Your new throughput would be...
HPS = 13953 * (1 - Crit Rate + 2 * Crit Rate)
HPS = 13953 * (0.85 + 0.3)
HPS = 16,046
A gain of 1,046 HPS or a 6.97% increase. The higher your crit is the larger the impact of the change will be. It has no change on how often you crit but simply the value of the crit when it occurs. So if you approximate the value of your crit today using a formula like this to determine what your throughput would be without any crits, then you can calculate what your throughput will be after the change is assuming nothing else changed.
This change will be roughly a 3-8% buff to all healers. This is just looking at this change alone however and not its interaction with other changes or class specifics.
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