Well, in Skyrim, I'm guessing we've all been to those forts and caves filled to the brim with wizards. Of all those casters, the ones that interested, and disappointed, me the most were the necromancers. As far as we're concerned as players, the necromancers are nothing more than frost mages that raise the dead, and while it's completely valid to say that they utilize cold magic because death is, well... cold, wouldn't it be more interesting for them to have their own branch of curses and debuffs? Maybe some Damage Over Time could be thrown in there to make them something a little bit more to be feared.
On top of this, the lack of these types of spells in the vanilla game makes it difficult to create a "pure" necromancer that curses and binds his foes while the undead do the muscle work? It would be a lot more sinister and fitting than a simple, run-of-the-mill Destruction spell.
What do you think? Does the necromancer system in Skyrim need a bit of improvement with darker spells and hexes? Is it fine the way it is? Or do you just not give a care?
I think it would be interesting if raised zombies could use their abilities (albeit under the necromancer's command.)
For example, zombies who were fighters could pick up weapons and fight for you; zombies who were stealth characters could still use those type of abilities (sneaking, backstabbing, etc.), and zombies who were mages would have the spells and magic skills that they had when they were still living.
You are right, now that I think about it. Something like Blood Magic I would say, even if it does not deal with death, it deals with blood. Spells that directly affect the body of the target, like curses maybe, make a foe's legs heavier would act like the slow effect. Also manipulating life force would be cool, spilling your own blood for damage curing off of your allies' blood. Boiling enemie's blood. I guess I'm inspired by Dragon age, but I think it would be more related to necromancy than your normal destruction spells with their elemental effects.
How about the various re-animation spells causing damage over time to the living or something, or at least like drain vitality? It seems to me like a living person being struck with that kind of energy would get pretty messed up, the stronger the necromancy spell, the faster/strong it affects the living.
I think necromancy could use some more indirect spells that don't necessarily deal loads of damage. Something like ropes to bind your enemy, Silence spells or Drain Health would be fitting for a Necromancer who lets his creatures do the musclework. Which brings me to the next point: Instead of having just one resurrected draugr, you should have the possibility to get more minions (they would have to be weaker obviously). Maybe doing some rituals to strengthen your minions during a battle would be great too (Sacrificing human hearts to give them health absorb abilities for example).
With all due respect, I do not forget that Soul Trapping can be considered a form of necromancy. But I do believe (correct me if I am wrong), that Soul Trapping creatures has been widely accepted, and only Soul Trapping a man, mer or beast race is generally considered necromancy.