I always found it frustrating that my Necromancer couldn't learn this spell.
(Especially since it was available only as an Easter Egg drop in BG.)
Wraithform is one of the rarer spells in 2nd edition that belonged to two schools of magic: Alteration and Illusion/Phantasm. According to 2nd edition rules, a specialist wizard may still learn/cast a spell that has two schools if one of the schools is permitted and the other forbidden. Since Necromancers may cast Alteration but not Illusion/Phantasm (and vice versa for Abjurers), they should be allowed to learn it. Is this fixable?