It's also true that regardless of a Necromancer wizard build, if there's enough buzz for it, they might make a "True Necromancer" full class at some point. But I'm not so sure what's so unique about the Necromancer that isn't unique about the Illusionist, Enchanter, or Conjurer, or Evoker. Or why any basic wizard shouldn't be able to grab some Necromancy powers if they wanted.
Anyway, my personal "first draft" take on a full-fledged Necromancer "Essentials" class would be kind of like this:
[sblock=Necromancer]
Necromancer
I will live forever, with your bones as my servants...
CLASS TRAITS
Role: Leader. Your mysteries enhance your allies at the cost of your enemies, draining your foes to empower those who protect you. Your secondary roles include Striker and Controller, depending on your power selection.
Power Source: Shadow. You have replaced a part of your soul with shadow, becoming a thing on the path to Undeath.
Key Abilities: Constitution, Intelligence, Wisdom
Armor Proficiencies: Cloth, Leather
Weapon Proficiencies: Simple melee, Simple ranged.
Implements: Orb, Rod, Tome.
Bonus to Defense: +1 Fortitude, +1 Will
Hit Points at First Level: 10 + Constitution Score
Hit Points Per Level Gained: 5
Healing Surges Per Day: 6 + Constitution Modifier
Trained Skills: Arcana and Religion. From the class list below, choose 3 more trained skills at first level. Class Skills: Endurance (Con), Heal (Wis), History (Int), Insight (Wis), Intimidate (Cha), Stealth (Dex)
Class Features: Life Drain, Undead Minion
Necromancers are legendary practicioners of dark, nefarious magic. Feared by most, shunned by the knowledgable, and seen as wicked, vain, corrupt, and hubristic, they exemplify the power of magic over life and death. Though most consider them vile villains fit only to be destroyed, the truth is that some necromancers practice the Art not out of a seething desire for world domination, but out of a complex amalgam of reasons. Some necromancers simply study the body in a cold, scientific way, treating the corpse as a machine of bone and sinew. Others seek to bring back loved ones that they have lost, plumbing dark magic to undo what fate has done. Still others embrace the dark magic out of fear of their own mortality, looking to extend their life, always one step ahead of the reaper nipping at their heels.
Necromancers delve into ancient ruins to seek lost knowledge and obscure, hidden lore, to discover the mistakes of the villains and failures who have gone before in the hopes that they will not become like them, or at least, that they will not fail.
Necromancers are leaders in the sense that they help their allies, but their main purpose is to benefit themselves. Allies are a means to that: the better the team is, the more likely success comes to the Necromancer. Necromancers fight at range, using their minions to protect themselves and control their enemies, and employing their life-draining magic to keep their allies (and themselves) up and operational.
NECROMANCER CLASS FEATURES
LIFE DRAIN
While many leaders employ powerful words of healing, Necromancers seize the animating force of their foes, and redistribute it as necessary.
Life Drain [Necromancer Utility]
With a simple gesture, you steal the life of your foes.
At-Will (Special) * Healing
Immediate Reaction;
Ranged 
10
Trigger: A creature within range becomes bloodied or reduced to 0 hp.
Effect: The creature is dealt additional damage equal to your Constitution modifier. An ally within range can spend a healing surge, and recover additional HP equal to the damage you just dealt.
Special: You can use this power only once on any enemy. Additional damage becomes 2 x Con Mod @ 6th level; 3 x Con Mod @ 11th level; 4 x Con Mod @ 16th level; 5 x Con Mod @ 21st level; 6 x Con Mod @ 25th level
UNDEAD MINION
A Necromancer creates and uses undead minions from the corpses she and her allies make. These minions do not last long, but they serve with the mindless, reckless obedience of an automaton ruled only by the hunger of death and the necromancer's strong magic.
At first level, you can create Zombie Minions. As you gain levels, you can create more powerful Minions. Minions obey your commands until they are destroyed, or something stops them.
In order to create a Minion, you need a freshly killed corpse, and you need to take a Short Rest, and spend a Healing Surge for each Minion you want to create. Healing surges spent in this way do not heal any of your HP. At the end of the Short Rest, the Minion is up and operational, and remains so until you take an Extended Rest, or until it is destroyed.
Minion Statistics: Minions have 1 hp each, and missed attacks do not damage them. Their Defenses are 10 + half your level + your Constitution (Fortitude), Wisdom (Willpower), or Intelligence (Reflex) modifier, with their AC being 2 higher than their Reflex Defense. They have a single basic attack against AC using your basic attack roll that deals 1d8+half your level damage (2d8 @ 11th level, 3d8 @ 21st level) and you can command them to execute this attack, or to move 6 squares, as a Minor action. Otherwise, they will not act. A minion can, however, be used as the origin point for any power you use, as if you were standing in the square the minion occupies.
Minions As You Level Up:
- Zombie Minion (Level 1): They can only move 3 squares, but their attacks deal additional damage equal to your Constitution modifier, and they have Resist 5 All and +2 Fortitude
- Skeleton Minion (Level 6): They gain +2 Reflex, and they gain a +1 bonus to attack rolls for each additional skeleton minion adjacent to them when they attack.
- Ghoul Minion (Level 11): They gain +2 Fortitude, and once per encounter, an enemy they hit is damaged and becomes Immobilized (save ends). While immobilized and next to a Ghoul Minion, the enemy is dealt damage equal to your Constitution modifier on your turn.
- Wraith Minion (Level 16): They gain +2 Reflex, and can Fly 6 squares when you spend a Minor action to move them. When they are damaged, they can roll a saving throw to negate the damage.
- Mummy Minion (Level 21): They gain +2 Willpower, and once per encounter, an enemy the hit is damaged and becomes infected. They are dealt Ongiong Poison damage equal to your Wisdom modifier (save ends), and each time they are dealt this damage, all creatures adjacent to them are dealt this damage as well.
- Vampire Floozy (Level 26): They gain +2 Willpower, and once per encounter, they can make a ranged attack at range 10 that does not inflict damage, but instead Dominates the target (save ends).
NECROMANCER POWERS
Three basic themes (plus utilities), but people can choose amongst them freely:
- Life-Stealing Powers (Con-based): When these hit an enemy, an ally can gain a related benefit. They deal damage, an ally gains HP (or temp HP). They inflict an attack penalty, an ally gains an attack bonus. They inflict a movement penalty, an ally can move.
- Fear And Dread (Control; Wis-based): Various fear effects: penalties, pushes, prones, stuns, etc. Deals Psychic damage. Keeps the Necro at a distance, and his allies up close.
- Enervation And Necrotic (Strike; Int-based): Various raw damage effects: blasts, bursts, ranged attacks, necrotic damage, sometimes with penalties attached. Also enhances ally/minion attacks with damage.
- Undead Qualities and Minion Buffs (Utilities): Grant undead qualities (like necrotic resistance, poison resistance, insubstantial, Resist All) to party members and minions; also buffs that just help minions. Necro is a "selfish" class, but others can benefit from her.
NECROMANCER FEATS
Some ideas for basic enhancements
- MORE MINIONS!: Create +1/+2/+3 minions with a healing surge.
- STRONGER MINIONS!: More durable, more HP, more damage. This should be limited: necros can add damage almost as fast as a Fighter can, and though it is less, the main limit on it is that it's easy for enemies to get rid of it.
- DIFFERENT MINIONS!: Alternate minions are good.
- Better Healing: Necros can heal a lot in battles, but its limited by their enemies, so they need more reliable sources. E.G.: if they're fighting a Solo, that's only two heals. A lot of this is contained in their Con-based powers, but we can throw a few kickers in, bonus HP's, temp HP's, Damage Resist, Defense Buffs, etc. that ride on their Life Drain.
- Body Mods: Let the necro gain undead traits via feats.
- PP: Seeker of the Eternal: Lots of ways to come back from the dead.
- ED: Lich: Oh hai never-dying.
Design Notes
- They're a CON-based class with Int/Wis secondaries. They thus have deliberately low HP and surge values, making them come out rather middling in the end. Still, they should be kinda "tough" for a Squshy Mage.
- Two main class features let them fill their Leader role and fill the classic Necromancer image.
- Life Drain should be useful in all combats, but it'll be more useful the more things there are dying. That's flavorful and interesting, but it probably needs some crash-course playtesting to make sure that minion battles aren't cakewalks with healing raining from the heavens and solo battles aren't deserts without a drop of heals. Possibly solved with "creature" language: Necros can drain allies that are getting beat down for heals for allies that are still up (which his hilarious, but leaves the party Defender up only 1 healing surge after being Life Drain'd on himself, which is weak heals. It's OK to be weak heals, but we need to still be effective w/ other healers.).
- Minions are variously strikery (with the minor action damage and some of their effects) and controllery (with the space they occupy and some of their effects). Gotta make sure the damage remains not-too-much, so it could probably use some playtesting to make sure we don't munch out flanking blows. Action Economy probably largely limits this: it takes a Minor action to move or attack, meaning its going to be an every other round thing in a fluid combat.
Well, that's the Rough Draft, anyway.
[/sblock]
