Viability of a Spell Speed WHM set up?

[Sumimi]

Edit : Sumimi your 534 SS is the magic number to exactly reach the 1,5 GCD hard cap, right ?

According to Purostrider's SPD chart, yep.

Teeechnically speaking you can reach the same hard cap with like 700 Spell Speed (using Dreadwyrm Weapon and food gets me at 685) and no fey glow, but you lose out on so many stats that you're pretty much only using that gear set for dungeon speed runs.