[Taqwus]

Undead have their own problems; the hordes being mindless is a curse in addition to a blessing. Watch as two dozen Illithids simultaneously mindblast your leaders because those are the only legitimate targets, for instance... and then the hordes dissolving rather than retreating. Dissolving's also a problem after an Earth Attack/Mind Hunt/assassin binge, and the unbreakable morale is a problem in situations where you *should* run to, er, remain undead another day. Mindless troops also never gain experience, and are poor at defending castles.

As for hp, well, for Longdead -- have you looked at Longdead Horse? IIRC, they've got a whopping 5 hp, possibly already combined with a never-heals flag.

Most everything above Longdead needs to be explicitly summoned, and tends to be tricky to do in quantity (Archers being an exception, as you get 10, but that's at Ench 7, IIRC; mass-Wights takes Conj 9). Ghosts can be, with a high-Death leader. But if they run into a Blade Wind, they and their relatives (e.g. dispossessed spirits) face Blade Wind with 0 prot and no protection from etherealness, since it's a spell.

And death magic *is* essentially a summoning path, with relatively focused constructions (primarily deathly effects like drain life and fear, and boosting death), few non-summoning rituals, and generally less-than-spectacular battle magic (shining against undead, 'tho, and decent in combination with astral). Blood is the other obvious mega-summoning path. If the summons for these paths weren't good, they'd be a pretty heavy disadvantage to something like Astral (recon, luck, ethereal, movement, multi-path boosters, enslavement, mind hunting, direct damage, dome, magic resistance...) or Nature (supply, regeneration, Vine Ogres, dome, Firbolgs, supply, light armor, supply, wolves, Gift of Health, supply, Lamia queen sorcerors, Charm, supply...), or Air (solo movement, lightning, storms, yet more lightning, can't forget Wrathful Skies, lightning weapons, lightning armor, seeking arrows, anti-missile spells, anti-missile items, mistform, Fog Warriors, others...).