Glad the removal of the glyph helped out, but I still think that there should be an option or conditional set for Frost and Unholy to disable it, just as there is for Blood tanks. I had to stop using this when I was frost because I pissed off so many tanks by using DG constantly on every CD. The tank said, at one point, "Stupid DK, why didn't you just choose to tank instead of waiting 15 minutes for DPS?" and then they group kicked me.
Don't get me wrong, I think Singular is pretty good for some classes, but to make it great, it needs a bit more customization and the rotations need to be tweaked. I've seen some CCs for various classes that offer you an option as to what type of rotation to use. One example would be Bowman. It gives you a rotation option for Solo/Party, DS LFR, DS Normal, and DS Heroic. I see that with Singular you really only get to choose between standard (for pretty much anything non-raid/instance) and instance (for raid/instance) rotations. Anyway, just my opinion, and I'd do it myself but even though they say that Singular is really easy for developers to make rotations on, I can't understand a single thing in the code. I was trying to add Blood Boil into the Blood AoE rotation for when I tank, but yeah, not so easy. XD