This is a complex topic so I figured it could use it's own thread. After having done a couple of runs with necromancer here are my thoughts and experience. Please feel free to add your perspective as well :)
I mostly played a vampire necro, and I think the dynamic between keeping bloodthirst sated and zombies is interesting and tense, but led to a situation where I was keeping very few zombies around because they were pretty weak anyway, mostly useful as a distraction until you have an army. I probably played super sub-optimally, but I felt like I never wanted to "waste" corpses, so I was in this weird self imposed position of not raising anything until mostly drained of blood which got much more manageable when I finally crafted a goatskin.
Once I grabbed vampiric touch at level three the class felt almost traditional warlock with the benefit of followers as meat shield. Sylvira was a constant thorn but I finally managed to kill her when I used the interior corner of a building to chokepoint her with dropped bone zombies in the doorway then vampiric touch as very long back and forth whittling her down finally dropped her.
There's a really tough dilemma with balancing the zombies with numerical potential and player character power itself but I have a few ideas, some light touch, some heavier and probably needing iterative approach if implemented:
1)Keep a mind to add (when appropriate) piles of bones to areas both secret and out in the open. The small stash of bones behind the waterfall was a welcome reprieve :) I also think it'd make sense to add pile of bones to occasionally randomly generate in the environment like rocks (but rarer). In the future with new maps, play up places like sewers and graveyards to be places where a smart necro could find stashes of corpses or bones.
2)Instead of balancing zombies out on like a sliding level or stat scale which seems like it could quickly become a massive headache, would it be possible to spawn a different tier of zombie based on the weight of the corpse? I think it would make sense if critters like rabbits and fox corpses gave appropriate critter zombies, humanoids made the ghouls we know, and beasts like bears and dragons produced a third tier of monstrosity. Personally I think the zombies you get should in some way be relatively proportional to the creatures you killed for them
3)Some extra weakling critters to pad out dealing with challenging enemies generally and the food/corpse balance would be a welcome thing. I noticed a few cats, dogs might be a suitable enemy for a couple of races as a "swarm" type. I almost have decided myself to add some irrationally hostile chickens somewhere :P
4)Possible to give raise zombie ability command functionality of zombies when used on something other than a corpse? Thinking things like
-used on self calls zombies to player(Wake up! lol)
-used on target focuses on enemy or sends zombies to wait for a bit at empty tile
-any action with it senses unlife (of just your own zombies)
These would I think alleviate some of the first "lighthouse syndrome" I got from trying to manage these guys and train enemies into them by manipulating the pathfinding.
5)Small one, but I'd mistakenly assumed Winds of Decay didn't damage your own zombies, it'd be quite nice if it either didn't or if the tooltip reflected that it damages everything in its path (the tooltip currently says it "damages all enemies" in a cone)
6)0.3 related specifically: Special Explosive/acid/burning zombie ability :D Totally not inspired by Cataclysm, I would never. Abilities that buff existing zombies or raising them as special types I could both see as interesting. Exploding corpse ability potentially?
*7)Bones and/or corpses might be interesting to explore as being throwable. I'd like to be able to toss either/or to raise one at a distance rather than dropping from inventory and scooting back. Bonus points for hitting Magnus in the face with a bloody rabbit corpse.