Pandemic causes your Bane and Curse spells to behave as if you have 50% haste (50% haste reduces GCD for casters down to 1 second).
Assuming that Haste and Pandemic don’t stack (ie you can’t bring your GCD below 1 second) that would imply that the second point in Pandemic becomes less important as your haste increases. In fact, using this assumption, at about 25% haste the only value of the second point of pandemic is in the secondary benefit where it will always refresh Unstable Affliction.
Hmmm /sigh I still think it’s worth it.. dropping off UA during execute would be annoying.. but still… worth thinking about.
But where would you stick that extra point, then?
The two obvious choices are:
Curse of Exhaustion
Soulburned Seed of Corruption
I’d probably choose the second.