I have this same exact problem. Let's brainstorm this out:
Foundation:
Skeleton Mastery: 20 Points (auto)
Raise Skeleton: 20 Points (auto)
Skeletal Mage: 1 Point (useful, prereq for revive)
Clay Golem: 1 Point (awesome versus boses, prereq for revive)
Blood Golem: 1 Point (prereq for revive)
Iron Golem: 1 Point (prereq for revive)
Revive: 1 Point (great minions, +skill gear makes it all the better)
Golem Mastery: 1 Point (powers up golem, prereq for summon resist)
Summon Resist: 1 Point (essential for keeping minions alive easier)
Now, for curse I don't add to all of them. Call me wrong, but I believe the only curses a summoner really uses is Amplify (for normal creatures) and Decrepify (for bosses). I believe that most other curses are too situational, and simply not as straight-forward and effective as Amplify and/or Decrepify. It may just be me, but minion damage > everything else.
Following these parameters:
Amplify: 1 Point (main curse)
Weaken: 1 Point (prereq for decrepify)
Terror: 1 Point (prereq for decrepify)
Decrepify: 1 Point (main curse)
I usually only add 1 point into curses because I feel that extra points are useless. With +skills, the curses are high enough. Casting a curse one more time isn't the end of the world.
Now that the basics are out of the way, there are 40 skill points (skeles) + 11 skill points (all else) being used. So, with 51 skill points used, 110total-51used=59left.
Poison Nova Approach:
Teeth: 1 point (prereq)
Corpse Explosion: 1 point (prereq and useful with +skills)
Poison Dagger: 17 points (Synergy)
Poison Explosion: 20 points (synergy)
Poison Nova: 20 points (main skill)
With this approach, only 3 skill points will be missing from a Poison Nova synergy (assuming your lvl99). This doesn't seem that damaging, especially with Bramble.
Bone Spirit/Spear Approach:
Teeth: 1 point (synergy, prereq for Bone Spirit/Spear)
Corpse Explosion: 1 (prereq for Bone Spirit/Spear, useful with +skills)
Bone Spear: 20 points (main)
Bone Spirit: 20 Points (main)
Bone Armor: 1 point (prereq, useful with +skills)
Bone Wall: 15 point (synergy, prereq for Bone Prison, useful with +skills)
Bone Prison: 1 Point (synergy)
This approach requires many more skill points. I think that this build is not optimal because of the lack thereof. I chose to add one into every synergy because the synergys add the same amount damage, so in this case having extra skills can be useful in certain situations and we don't lose any skill points. I noticed a choice between which synergy to dump the extra skill points (14) into. I chose to add to Bone Wall because:
1-It doesn't matter which skill was added to because they all improve the damage of Bone Spear/Spirit the same.
2-Teeth won't be used even if all of the extra points were dumped into it. It simply wouldn't be strong enough.
3-Bone Wall seemed like the most useful in comparison with: Teeth (an already inferior spell to Bone Spear/Spirit) and Bone Prision (a seldom, if at all, used spell).
Overall, I feel Bone Spear/Spirit would be a bad idea.
Max Summoner Approach:
Corpse Explosion: 20 points (main)
At this point, I know you must be saying "I though this was an approach to maxing summons". The answer to that is yes, however, Corpse Explosion is too good to be ignored. With just 20 point into one skills, as opposed to other approaches that require 20 points into multiple spells, Corpse Explosion will WRECK crowds of creatures. I can't stress enough how awesome Corpse Explosion is in PvM. With 20 hard points and +skills, it can hit every monster on the screen! The best part is, as the monsters get stronger, so does Corpse Explosion. Not to mention that Exploding your slain enemy's corpses into the faces of your live foes just adds to the badassness(omg lol, this didn't get spellchecked--it's actually a word!
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) of a summoner.
**All skills hereafter add onto the points added above, simply to keep within the same parameter of 59points remaining**
Revive: 19 points (gets stronger with harder monsters, sufficient damage, great meat shields)
Skeletal Mage: 19 points (lengthy explaination below)
Whatever you like: last point
For Skeletal Mage, I know they aren't THAT effective in Hell. However, the 20 points are ALREADY in Skeleton Mastery, so it would seem wasteful not to use Revive and Skeletal Mage. With +skills, the mages would actually be alright. Besides for doing, at the very least, mildly impactful damage, they are also great meat shields.
You may notice that I didn't add any extra skills into a golem/golem mastery.
Simple, straight-forward, and practicle is how I would describe this build--and I like it a lot! Both Revive and Corpse Explosion get better with tougher monsters, and both skills can be whipp ass in certain circumstances. The regular Skeletons, possibly with a might merc equipped with Pride, are the solid foundation of the build while the other minions are the extra umph. The Skeleton Mages really just extra, and a dump for otherwise useless skill points. The nice thing about this build is that it would function without the Skeletal Mage skill points, so you don't have to be lvl99 to effectively maximize the build (like you would if you were using Poison Nova/Bone Spirit and needed synergies).
In general, I seem many errors in the way people build necromaners. I am a non-nonsense sort of guy, and I don't like to add any skill points unnecessarily. Adding extra points into curses just seems lazy,
CAST THE CURSE TWICE IF YOU NEED TOO! Likewise with golems; they can also be recast easily. With lots of +skills gear, a good CTA for powering up your minions, and auras for increasing your minions' damage (Fantacism, Concentrion, Might), your summoner should be rocking it.
These are just the three logical conclusions that I made about building a summoner. The split that I noticed was the difference between minions being the focus of the build or minions being a supplement to the build. If you have any different ideas or feel that something I said doesn't make sense/is wrong, don't be afraid to speak up and question it.