There are lots of very decent major glyphs for tanking, but this one strikes me as more of a Frost DPS glyph.
Looking at your glyphs, I'd replace blood tap with pestilence, and the icy touch glyph with frost strike, rune strike or dark command, depending on if you are in raids (dark command becomes more important in taunt tag fights) and your specific play style.
For threat on a single target, nothing beats the rune strike glyph.
Looking at your talents, you are DW frost but have neither chill of the grave or scent of blood. If you are throwing out as many rune strikes as you can, you'll be RP starved. YOu should seriously consider getting cotg or sob.