When Blizzard reintroduced Detection via the Glyph of Detection, I was ecstatic. Trap detection had been baked into the class when Detect Traps was originally removed, but that didn't stop rogues from waxing nostalgic about Swirly Ball. Warlocks wanted their green fire, warriors were trying to use Titan's Grip with polearms, and rogues begged for Swirly Ball back. The Glyph of Detection is the perfect minor glyph because it's fun and it's purely cosmetic. Or is it?
Balarak, who is unfortunately a hunter, discovered a secret rogue event while infiltrating Ravenholdt Manor. Nobody expected what he found there. Ghosts and spirits, a hidden tribute to the Mistborn Trilogy by Brandon Sanderson, a rogue-only item with amazing capabilities, and the implication that maybe, even in this age of data mining, we haven't found everything WoW has to offer.