The Necromancer is Underpowered Reason 4: Summoning isn't reliable

So far, I've presented problems pertaining primarily to poison necromancers, bone necromancers, and melee necromancers. Those familiar with Diablo II will easily notice the topic that I've avoided up to this point. The necromancer has a whole skill tree devoted to summoning and summoners are the most popular type of necromancer. Even granting the inferiority of other types of necromancers, one could simply assume that summoning is where the true power of the necromancer is to be found. However, the single character I've spent the most time on has been a summoner, and I contend that summoners have some major problems.

Just to be clear, unlike with the poison skills, the bone skills, and melee, I will never make the claim that the necromancer is outclassed in this particular area by the other characters. By this, I mean that I fully acknowledge that when it comes to using pets as a primary killing method, the necromancer is the most powerful. That's not much of a point in his favor because pets aren't generally a viable primary damage source anyway. The amazon's Valkyrie and the assassin's Shadow Master are not meant to sweep out dungeons by themselves. They are utility. They distract monsters, tank bosses, pick off occasional stragglers, and add a little damage during intense fights. The only character other than the necromancer that can run around with multiple pets is the druid. And I suspect that a summoner druid wouldn't be that great anyway. The druid does get excellent utility out of his pets when used alongside his other skills, though.

The summoner definitely has some things going for him...

1. Each point put into Raise Skeleton makes skeletons stronger, and every three points put into it gives another pet. The same goes for Raise Skeletal Mage. Every point put into Skeleton Mastery also increases the potency of these pets. And every +skill that affects these keeps on giving all of those bonuses. So the summoner gets more out of +skills than just about any other build in the game. Maxing Raise Skeleton only allows for 8 skeletons. But with +skills, my summoner went up against Baal with 14 of them. And to reiterate, it's not just quantity: those skeletons are also stronger.
2. Most monsters never get the chance to touch the necromancer. Defensive measures are still necessary. Having high resists is a good way to stay alive. But once a summoner has enough pets, they serve as a sort of protective barrier.
3. Amplify Damage makes everything die faster and breaks most physical immunities.
4. The skeletal mages have fire, cold, lightning, and poison damage. Nothing resists all of those. Unbreakable physical immunities are generally not much of an obstacle.
5. The golems make decent tanks.
   
6. Skeleton Mastery also makes Revived monsters stronger. They're virtually impossible to kill.
7. The summoner is one of the least item-dependent characters possible. Powerful equipment is good for a summoner, but it's not as vital as it is for most builds.
   

With all that, one might wonder what the problem is. Well, I usually play on PlugY. So back when I was working my summoner through Hell, on /players8 like I'd been playing the whole game, I suddenly got the Uber Diablo event. I was in the Durance of Hate at the time. I went back to Act I and let Uber Diablo spawn in place of Rakanishu, so that he wouldn't interfere with my getting to Mephisto. I ran up to him with my army and watched as they were wiped out. I tried replacing my fallen skeletons with new ones, but quickly ran out of corpses. I managed to save myself from dying thanks to my "Enigma" runeword's Teleport and some potions. I went back multiple times, bringing my full army of skeletons, my golem, my mercenary, and as many revives as I could. I tried teleporting my full army right on top of him. I tried teleporting around him and letting my mages blast him. Nothing worked. I couldn't kill him. My army could damage him enough to beat his regeneration for a while, but then he'd kill enough of my skeletons that his regeneration was outpacing our damage output. I ran into Uber Diablo later with that same character, facing a similar outcome. And then, amazingly enough, I got the event a third time with my summoner. The third time it happened, I remembered to switch to /players1 immediately. He spawned in Pindleskin's place. This time I brought urdars. He still wiped my army out, but at least I cleared the area of other monsters. I went back to the River of Flame and got as many urdars as I could. I brought extra potions and made sure to keep my mercenary alive. I used my "Beast" axe and joined in on the action myself. I used Lifetap after he hit us with a big spell and kept him under Decrepify at other times. It took a while and my Revives started dying, but I did kill him.

Perhaps that anecdote makes it seem as though I'm expecting too much. After all, this was an event monster, substantially more powerful than anything in the normal game. Against almost any other boss, my skeletons would be more robust and I'd be able to go back and grab some more without the boss regenerating if my army did perish. I was actually a bit worried about the Ancients in Hell for this reason, but they ended up not being a problem. However, I'll note that I also got Uber Diablo when my poison necromancer was in Act I. Even though it did take a while, I beat him rather easily. Shut up, that's not proof that necromancers are actually good.

I think what this really illustrates is that with summoners, if something goes wrong, recovering is an ordeal. In Nightmare difficulty, Baal depleted my army considerably, but they finished him off. In Normal, I actually did have to go back after Diablo wiped out all of my skeletons. At high levels, with godlike equipment, a summoner's skeletons may be strong enough that most enemies won't pose a threat. I did have to do a whole lot of summoning in the Halls of Vaught when the guest Tomb Vipers decided to destroy half of my army Fortunately, I had so many skeletons that they were able to win, even if it was only barely. But this is all just mitigating a problem that, for most characters, doesn't exist. I suppose that an amazon might need to worry about running out of arrows. But no other character has to worry about running out of corpses.

The need for corpses is actually quite irritating. Druids, amazons, and assassins don't need corpses. They can summon their pets out of thin air. The only pet the necromancer can get without corpses is a golem. If golems could become real powerhouses, that might help balance things. Instead, the golem is one of the least damaging things in the whole game. This is something that baffled me when I started building characters in the other classes. Why wouldn't a golem be able to do some damage? Even for a powerful summoner, skeletons do tend to die and need to be replaced. Revives are much hardier, but they only last three minutes. Sure, monsters are numerous in this game, so potential corpses are common, but some areas lack a ready supply of corpses (you can't replenish your skeletal army while fighting Duriel, for example). Some monsters don't leave corpses behind and some monsters have abilities that destroy corpses. And in addition to needing corpses to replenish the undead army, summoners generally make use of Corpse Explosion to speed up gameplay. That's another expenditure of precious corpses. Speaking of speeding up gameplay, summoners are slow. And speaking of relying on Corpse Explosion, well, more on that later...