Wow, this is an old one. I honestly had trouble remembering that I wrote that. I mean it is me, obviously, but it's been 6 years. Must have been around the time I started on the board, I think.
Anyhow, let me see if I can shed some light on some things.
First of, yes, necromancy is about life and death, as well as usual magic is about life and death. I think it is just a matter of perspective. For a wizard, death is the absence of life. For a necromancer, life is the absence of death. It might be splitting hairs, but the wizards perspective plays a huge part in what they are doing, that's why I am making a point about it.
I'd wager, that you would be able to break the laws with both necromantic and normal magic (leaving you with black magic and black necromancy). You can push life into a corpse or you could shove death out of it, the end effect would in both cases be a zombie. The same goes for Kumori saving the man's life. She kept death away from him, instead of forcing life into him. The end effect is the same, but the approach is vastly different. So different in fact, that her approach might actually be easier than anything Harry or even the Merlin might have accomplished.
I'm pretty sure we're on the same page with will and energy and such, maybe I worded it poorly. The wizard needs to shape his spell into the effect he wants, that is part of what his will does. He can also fuel it with his will, and that's where he doesn't need any external energy sources. He can get more bang for his bucks, if he can draw energy from additional sources, of course. I don't see how my quote and your "Will and energy" argument contradict each other.
I think we mean the same thing, only you say "crutches", I say "symbols". It's purely speculative. There might be people who can calculate complex mathematical formulas in their heads, but most people need to do auxiliary calculations to be able to get anywhere close to the answer. From the perspective of someone who can do it, those auxiliary calculations are certainly a crutch, but if they are required by the vast majority, is it really fair to call it a crutch? It's a tool, and some people can do without. Granted, symbol might not be the best word, but I still like it. "Tool" feels like it is limited to physical tools like symbolic links or focus items, and that's just not the case.
Harry explains the use of words to shield the mind pretty much for every spell he casts in the first three books (well, it feels like it. I can't find a quote right now. If anyone has a digital copy to search through, it would be appreciated). He states that the word is a symbol for the wizard to file away the spell in his mind, to have a construct, a symbol for everything that the spell is. Like when I say "Hammer", and you have not only the image of a hammer in your mind, but your body also remembers the movement necessary to use a hammer to drive in nail.
Now if you have an actual hammer in your hand, it would be much easier for you to actually do the precise motion. If you had a mark on the wall, you will be more precise in making the motion exactly the same over and over again, even if you don't hit an actual nail, because you have a clear visual target.
I think it is very similar with a spell in the dresden verse. You can apply your will directly, we've seen demonstrations of this by Vadderung, the Mothers and even the Lords of outer night. But those are old and immensely powerful beings. Everyone else needs to apply what I call symbols. It is extremely difficult to affect something by pure will, but you know what fire is, what it behaves like, what it does, so instead of pure will, you shape it into fire and throw fire at your target, because that's something you can understand. The words you say when casting the spell are just refining it even more, so "Fuego" for Harry is not only a word for fire, but it is the mental image of his lance of fire, the mental processes it entails, the motion of his arm, and so forth.
I see symbols as pretty much anything that makes your spell deviate from an application of pure will. The elements, words and focus items of evocation, ritual items in thaumaturgy, what you call "crutches". Yes, you can do anything as pure will, but using tools and symbols is much easier and sometimes the only way for someone to do it at all.
Well, a lot of rambling on an old topic. I tend to ramble on, if nobody stops me. Also, this is pretty much all my opinion, I don't claim to know the fabric of a fictitious universe that hasn't entirely been created by myself. This is however my interpretation of what has been presented.
TLDR:
- Necromancy is diametrically opposite normal magic, both can be black or "white"
- I don't think I contradicted the "Will and Energy" assumption
- Symbols are everything that makes a spell easier to cast, beginning in the choice of elements