There's no rule that says Necromancers have to be "bad" or "evil". The Diablo 2 Necromancer, for example is one of the most good people in Diablo 2, here's his story:
http://www.battle.net/diablo2exp/classes/necromancerhistory.shtml
You're talking about a game (4E) where you can be a good person even though you have a pact with either
Satan's bestest bud or the most
utterly ruinous powers from outside the bloody universe! If you don't have a problem with that, I have no clue why you would have a problem with a good Necromancer, especially if he summoned undead beings "out of thin air" or from defeated enemies, rather than defiling friendly bodies.
As a DM I've seen three Necromancers played, two were NG, one was NN, back in 2E. All of them were great characters with atypical ethics (I've never gone with this "making mindless undead out of corpses is inherently evil" stupidity - and I was encouraged by source books like
The Complete Book of Necromancers that I was right not to).
In short, yes, I expect to be able to play a Necromancer, and I sure as hell don't expect them to automagically be regarded as "evil", any more than a Pally or Cleric is automagically "good" because they work with healing and protecting. 3E had a lot of dumb stuff with "Evil" and "Good" descriptors. 4E has no mechanical alignment idiocy, THANK GOD, so I don't see what the problem is, quite frankly.
The only
real issue to resolve is economy of actions, I think, and if they can do that for other summoners, they can damn well do that for Necromancers. If they can't then they probably need to look at Diablo 2 and other games for cool Necromantic abilities which don't directly involve summoning, or involve very temporary summons.
Note that for a
PC Necromancer to be a Necromancer, I don't need him to have permanent animated corpses hanging out with him. That's cool but if it doesn't work, it doesn't work. Summoning undead-type being and so on, though, and scary death/undeath-related effects is AWESOME so should be in.