I said it before; I'll say it again - Necromancers are invariably the villains. Of course, when I announced my opinion on this subject earlier, the thread was promptly shifted to 'off-topic'... go figure.
It's a cruel world
I myself see the ethics of the class as being similar to that of a rapist's, thief's, murderer's or slave-trader's: no matter the rationalization, they're beyond the pale of decency, and shall never deserve or acquire proper redemption. At best, they're tragic anti-heroes, subject to the corruption that taints or perverts anything decent or sacred. That players enjoy games the feature such reprobates says a lot, I guess, about gaming culture. It's a harsh assessment, I know, my dears. But think it through, and you'll invariably come to the same conclusion.
That said, wasn't Diablo 2's druid also considered a summoner class? True, ravens, wolves and direwolves weren't as interesting as skeletons and golems, but it was a step in the right direction - what was missed entirely was the classical druid's ability to both curse and to heal. Adding shape-shifting was a bonus (werewolves? cool!), especially with the available attack and damage bonuses.
If a summoner class is introduced into Torchlight, then I'd hope to see a character class that avoids necromancy entirely but develops the idea of a transfigurating nature mage (for ease, call 'em Chthonians) a bit more.
What would this class be capable of? Learned in occult sciences, Chthonians would have the ability to summon "natural" creatures (predator birds and mammals); shape-shift to resemble an opponent (wouldn't it be fun to look like a yakotaur or storm-bear for a few minutes?); curse and heal (I think these abilities speak for themselves).
As always, this is just a suggestion.
P.S.: And I'll continue to insist Cheny (not Keith Richards) was the ideal vision and practitioner of necromancy - P.