I agree that Necromancy is quite weak, The starting cost for Necromancy is a bit higher than the other skills, making it a tough choice for a first skill. And it'd take some time to reach level 12 without the exp gain skill to obtain Necromancy along with gold gain. Otherwise it'd be your third skill after exp gain, by this time I doubt you'd need it. And if you didn't have the gold gain skill it's unreasonable to purchase Necromancy and make use out of it.