Let me also add that while the AA adds the green text to Death March I, the effect does not apply to Insidious Whisper, Blasphemy, Hateful Slam, Grave Sacrament, Hateful Respite, or Shadowknight's Furor. The fervor buff does seem to change the value on the damage portion of those spells/CAs that have them. So all Death March abilities fail to modify threat.
As of 3/9 live update, the green text is now on DM 2 and 3, but still doesn't increase threat on taunts.
The effect text that was on of "Increases base taunt amount by" was misleading, as what the effect actually does is increase the effect as if that much extra potency was applied to the ability. Unfortunately when a lot of those effects were added, a lot of them used a generic and not entirely accurate description such as that. We updated the description to be more accurate to what it does, and we have verified that it is granting that increase.