Many summoners are still deadly random enemies. On nightmare and insane, summoners are the biggest threat, with corruptors of course
Can't say I agree with that at
all, actually...
Corruptors do straight up blight damage that has reducing returns. I'm going to avoid the hell out of someone with Fearscape/Urh'rok, of course, but I always would, and at least Urh'rok "just" gives 50% speed at those levels of talents.
Summoners produce enemies you have to teleport away from or status-letting them get swings can produce some very ridiculous results-but they aren't especially great at stopping status. There were times in Gorbat where I just tanked them, too, as their returns start diminishing past around L10 too-there's not much more powerful you can be once you're **, for some of them(War Dog has a lot more level scaling).
Compare this to "Anyone with Freeze" or "Anyone with Breath attacks", who respectively can deal insane damage(1800 damage, Elandar? Really?) and have insane range/great damage/status that the AI can use from well out of LoS(20+ was pretty common, with Sand Breath generating 20 turn blinds), and it pales badly in comparison. And don't even get me started on
Archers, who almost always cap out Physical Power thanks to Bow Mastery, and can legitimately deal Freeze level damage with Steady Shot. Or enemies with Essence of Speed. Like Elandar, who had 253% Global speed. Or Shadowblades, who have insane damage output, Essence of Speed and Shadow Veil-I never ran into one with the full combo, for which I am very, very glad.
I think the only time Corruptors really compared was late, when they started pulling out L10+ Bone Shield. Summoners were always "Go away and it'll be better", like a Necromancer except worse(Did I mention those summon fields of 10~ minions often, at full screen range? With large level advantages, so that by the time you see them, they almost always have Reassemble? That is an instant run.). Oh, and Burning Hex is upgraded to potentially lethal status from debilitating, but I associate that more with Dreads. Otherwise, though...