I just think that this dicotomy between elemental and physical damage fuck up the whole build. Amp. Damager vs. LR, Infinity vs. Concentration, Brambles vs. Enigma, Beast vs. Hoto...
I'm trying an summon build 100% based on elemental damage. Mages, infinity, poison nova, bones for tanking. I'm certain that this is no match for a pure poison or skellymancer, but it's just for fun anyway.
Actually both skills are veyr good (teeths are good too!).
For PvM i really use Spear most of the time. Teeths is used to kill very low HP mobs (fallen and last act imps basically) and spirit i use to kill bosses and super uniques.]
Also, the travel speed of bonepsear is faster, wich also increase it's tatical value in pvp!
On normal i allways kill bosses via iron maiden + clay golem after all the skely's get killed. Also, some points in summon resist will help your minions to resist the massive damage done by diablo, baal and mephisto. Later those points becomes quite useless since your skellys can kill anything w/o summon resist and the skill scales pretty bad with 10+ points (and you can reach 10 with items). Still, 5~10 points will help you alot in early levels and since skellymancers have like 40 points left to spend, those points used to make your low lvl life easier won't hurt a bit (unless you plan to get nova).
I wish the necromancer summon tree were more balanced. The only skills that truely worth more then one point is raise skeleton/skeleton mastery.
I didn't see any point in adding to Summon Resist, as my Summons can easily be resummoned, there's no need to up their resists. A 1 point wonder, if I may say so myself. With that in mind, I was able to beef up my Skele Mages (damage for the most part), by maxing them out.
Against bosses the summon resist is very usefull because you can't resummon your minion that easilly and bosses do massive elemental damage.
With really godly gear you'll be able to clean up bosses even w/o SR but i recommend it for times were you don't have CTA, Beast, Mercs, etc...
Something like 10 points is good enough. Anyway, skelly mages are allways to weak. Their damage are not buffed by AD, auras and other buffs. Their damage are also fairly low, specially because of enemies high resistance. Unffortunely skelly mages are underpowered =/ Lets hope for a fair buff in future patchs !
Thats right. They buffed the two bests offensive skills for PvM (Ce and PN) instead of buff underpowered ones like Mages and the other poisons. I didn't like the necro changes...
About the build:
I would not use Mages. They damage are very low even if you're using Lower Resist.
Those 19 points will increase the damage of each skeletons by something like 40(avg.)...
Instead i would put those points in Poison Explosion/Dagger to synergize with nova, increasing it damage by alot more, expecially because PN hit everything in the screen at once.
And I suggest the last 3 points could be spent in Din Vision, Confuse and Attract (some times they are very usefull).
And since you're using Nova i would stick with Mara's...
I agree with everything else, specially the items (people usually overlook the fanatism aura from runewords wich works amazeling well with skeletons). I will only suggest a variant, that i dunno if it will work or not, but just for testing:
Instead of Nigma you use brambles (because it greatly improves nova's damage) and use a Act I merc with faith bow (stronger fanatism). Then, instead of Beast weapon, get a hoto.