Because WW was made into a talent and they do not make glyphs for talents.
Pretty pointless considering that the glyphs already existed, but what can you do?
Couldn’t they just do something like talking to trainers like you can still have the val’kyr instead of the gargoyle? Or like your blink spell as a mage goes the direction you’re moving with a similar choice mechanic.
They really need to re-assess the dk talents anyway, we haven’t had very good choices for years now.
And while they are at it give frost an actual secondary special ability type to just frost everything, likely removing dancing rune weapon from blood and giving it to frost along with various other weapon summons.