Originally Posted by
Dubalicious
There's always a little misunderstanding about the Glyph of Illumination. It would be a GREAT glyph if the tooltip stopped at the "good" part (the only part you're referencing here). Unfortunately, the glyph also causes you to lose 10% if your spirit regen from your passive "Holy Insight" which likely averages out to anywhere from a 1200-1600 MP5 loss (for me it's right at 1,550 mp5 lost *just from equipping the glyph*)
So it actually DOES have everything to do with gear, because the more spirit you HAVE the more you effectively LOSE by equipping the glyph. In terms of mana-regen *Glyph of Illumination is a NET LOSS* without considering any other options. In other words, you would be better off with no glyph at all in that slot.