The discussion about Animate Dead is interesting. Though there are no formal limits on the spell, the flavor text is explicit. In fact, it reminds me of the August 2012 play test package, when there was a specialty available that was the Necromancer.
The Necromancer was awesome: it was flavourful; it was not restricted to a single class; it had no alignment restrictions of any kind. Not all were evil, but they may encounter prejudice. All that I'm fine with, and I'll admit that I am really sorry that it has been removed from the playtest materials, since it would have been great to see this develop. But, and this went almost entirely without comment at the time, it had a truly terrifying first-level ability.
Aura of Souls:
When you slay an enemy, you reach out to seize its departing soul, converting it into your own vitality.
Prerequisite: Able to cast at least one spell
Benefit: As an action, you can capture the fleeing life energy of a creature that has died within the last minute, transforming it into a spirit that hovers near you. The creature’s corpse must be within 50 feet of you. You can have no more than two such spirits at your disposal at any given time. These spirits dissipate after 1 minute.
When you cast a necromancy spell, you can destroy one of these spirits to give yourself advantage on one attack roll you make with that spell, or give one target disadvantage on a single saving throw made against that spell.
The mechanical benefit was modest: comparable to the Guidance spell. But look at that flavour text!
The Necromancer could seize a departing soul, and then destroy it!
This was (a) a first-level ability, that (b) was not called out as necessarily evil, even though (c) it would apparently (if we take the flavour text literally) prevent raising from the dead, resurrection, etc.
Compare this to the furore over Animate Dead, where the spell merely bestows undeath upon a pile of bones or a corpse and we see how small these stakes really are.
Indirect language that says nothing about destroying souls. It uses something called "undeath" with no actual sense of interfering with the deceased and her divinity (if any).
Animate Dead is, in comparison, lame in its shock value, and doesn't come close to violating the bounds of good and/or law in the way that Aura of Souls did.
Here, then, are two extremes in the approach to Necromancy spells. The right solution is somewhere in the middle. A Necromancer Specialty (available to all spell casters), that provided some special abilities without reference to necessarily evil acts, and similarly without reference to de-protagonizing options for other characters (where something might happen to their characters because of flavour text rather than the actual mechanical effects that have been defined) is both logical and could be made available within the current playtest parameters. That's what I'd want.