I just replaced 264 shoulders with Sanctified Lasherweave Pauldrons completing my 264 set, and my GS went down like 12 points...why is this? I don't think gear score is taking set bonuses into consideration, I thought the extra heals I would be doing would increase my GS by a good amount but nope.
for the record, the shoulders i had on before were Shoulders of the Frost-Tipped Thorns, and with my current spec, I was over haste capped. My GCD is still one second and my regrowth is still under 1.5 seconds so I'm still capped.