Ah, the Undead. A classic creature type from DnD. From the fragile skeleton, to the deadly lich, they come in all shapes, sizes, and powers. Truly, they are to be expected in any campaign. But with their ubiquitous nature, there comes a problem. They laugh in the face of certain individuals, whilst cowering from others. The humble rogue, bless her soul, has her blades dulled by these most nefarious of beasts. The low level wizard or sorcerer can do little other than cower in terror, as her trusty Colour Spray is reduced to naught but a simple parlour trick. And oh, the soulful bard, her songs going uncared for by these creatures of horror. They must simply pray and hope that a passing Good cleric or that champion of law and justice, the paladin, hears their pleas for aid, and dispatches the foul villains posthaste. These hordes of darkness must be thinned, to allow those without divine providence to proceed in their journeys.
(In other words, Alice complains about NWN module makers who make heavy use of undead, without supplying alternative answers to deal with them. Especially if said module makers don't make potions or scrolls of lesser restoration available for sale so that you're stuck weaker than a kitten.)