Death & Blood a little borked?

[Taqwus]

Death summons are unusually vulnerable to Dust to Dust, Wither Bones, Solar Rays. Some also suffer from a tendency not to play well with others (cold aura, disease spreading) and this is especially true of death battle magic (area life-draining / disease-spreading / decay-causing tends to be indiscriminate, for instance.)
Death magic also lacks friendly fliers, has few mounted units, provides fairly limited forging, and is very bad at providing other benefits such as countering other magics (no domes or ward spells, say), providing mobility (Stygian Paths is late, hard and dangerous), no troop enhancement spells et al. It's quite strong at what it focuses on, but hopeless at others.

Blood is similar in degree of focus. It's great for summons, especially in winged summons, but lousy at most other tasks.