Ah... I don't know about using both glyphs. You'd have to give up either Glyph of the Ghoul or Glyph of Dark Death/Unholy Blight... which I think on a DPS basis outshine the use of both.
However, if we had ONE DK with Glyph of Disease...all other DKs would benefit immensely from their diseases being auto-refreshed.
Also, I think this is a better 3.1 build.
http://ptr.wowhead.com/?talent=jZG0xZfMhILcdgcqMcsutYou give up 1 point in Necrosis (which in its latest incarnation kind of sucks because it doesn't dip into any of our modifiers, just a straight up 20% of whitedmg) for Bone Shield (20% dmg reduction is amazing, even for DPS.. and a flat 2% dmg increase is nice considering the ease of keeping it up). Also, I'm not quite convinced yet on the value of Ghoul Frenzy since it costs an Unholy Rune. The healing would be nice for Ulduar (I read that there is a ton of AOE going on in there)... but it seems way too situational. I'd have to read more theorycraft on this before I carve it in stone, though. But I would definitely definitely definitely pick up Bone Shield.