The Original Blackout talent read as this:
Shadow Priest Talent (Classic/Vanilla to Wrath): Gives your Shadow damage spells a 10% chance to stun the target for 3 seconds.
The Turtle WoW Blackout reads as this:
Shadow Priest Talent (Classic/Vanilla to Wrath): Gives your Shadow damage spells a 10% chance to stun the target for 2 seconds.
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I'm not sure why the stun duration was nerfed, since just about every class has received buffs in PVP on this server, but there's no need for Shadow Priest to have its stun nerfed. We literally only have a lengthy cd fear as CC you can actually use in combat. This nerf makes no sense to me.
Other classes received new spells and mechanics on Turtle, Shadow Priest seems to have been nerfed for no reason.