Sorry, I'm not suggesting that Necromancers are evil in any way, just that a lot of these classes specifically don't have an outwardly positive personality.
Necromancers are of an extremely gritty religion. None of the classes chosen have an inherently positive radiance about them, so Paladin or some kind of Holy user would have been a good match I think at least.
It's less interesting when everybody in the party is gloomy or gritty in some form or fashion. It's actually a reason why I liked the Templar in D3; Dude was a righteous prude in an otherwise cynical environment, and it was a good change of pace from everybody screaming about death all of the time.