-First thing’s first: look at endgame gear pieces. Even a few things like relics/belts/amulets that add +1 to all skills in Inquisitor/Necromancer will give you more points to play around with. It’ll also give you an idea on just how far you can push your main abilities damage.
-Don’t know why you went Aura of Censure as you appear to be going Aether.
-Points in Reaping Arc confuse me. You have nothing else in this build that indicates you want to do an attacker.
-Move all points in Word of Pain to Death Sentence.
-Allagast’s Arcane Net does not convert Lightning Tether’s damage just so you know as I believe it is counted as a secondary effect.
-Since you took Word of Arms, I presume you want to go 2-handed? I would consider a focus instead for the extra CDR so you can use Storm Box/Siphon Souls more often.
-You definitely want Widow.
-Not sure why you picked up Reckless Tempest as you appear to be going Aether.
-Do consider that while Spear has amazing nodes that other T3 (and some T2) celestial powers are better. There’s a myriad of ‘X to Aether’ conversion so you have plenty of options.
It is possible to balance Aether/Lightning together (Allagast builds can do it off the top of my head) but you need to decide clearly what you want to do as I get the impression you are trying to do some sort of 2-handed caster/attacker hybrid and both parts want fairly different things (casters want CDR/casting speed, attackers want flat damage, attack speed, a replacer/WPSes etc.).
My suspicions are that trying to do both means you will be less effective at either in comparison to a dedicated caster or dedicated attacker.
For example, you want to do a Soul Siphon/Storm Box character, so why work attacks in between when you can use a Focus for cooldown reduction, gear pieces like Allagast’s Masterpiece or the Eternity relic or Time Dilation to allow you to spam these more often so you don’t need any auto attacks?
You could work in another skill as nuke like you said. Reap Spirit, Bone Harvest (with Elemental/Vitality to Aether conversion) and Rune of Hagarrad (with Elemental to Aether conversion) are all solid options.
A casting skill might not be a bad idea either but I probably wouldn’t say a channelling skill like Drain Essence.
Can’t open GT (no idea why you didn’t just post the link), but from the comments in the thread i assume you are going elemental/aether dmg?
Imo, vitality would work much better (2x Decree of Malmouth to convert lightning dmg and it conveniently gives you a 30% vitality res shred for 1 skill point). This setup works amazingly with Rune of Hagaragawhatever (Conduit for converting pierce to vitality), should work perfectly fine with storm box (in theory, Storm box would open up an amulet slot for the Radaggan set, but the Rune is so broken and combos amazingly with Siphon). I used the Dark One set in my setup, with the classic Hourglass vitality devotion setup (Lantern, Obelisk, Rattosh, Hourglass + random blue and red nodes).
Edit: now that I think about it, why Storm box instead of RoH? Both Storm box and Siphon do the same thing, they clear mobs while you kite. What would you do with those skills vs a Nemesis, run around for 15 min? Use Chillspikes or Winter king?
There are hybrid builds, but you can’t just throw random skills together and auto attack in between cooldowns. If you want to make a hybrid caster, you need to focus on skills that have at least one of these properties:
Works well with autoattacks. Either using an attack animation instead of casting animation (transmuted Blade Arc, Shadow Strike, Ring of Steel, transmuted Primal Strike…) or empowers autoattacks (Bone Harvest and A. Blade Burst leave a buff to base damage after casting).
Has very high % weapon damage. This allows you to place damage over time effects after casting and abuse charging autoattack skills like Savagery to improve the damage of your spells.
The advantage of hybrids over spam-casters and attackers is that you can apply high damage over time effects on dangerous bosses and run around instead of tanking them. The advantage of hybrids over cooldown-based casters is that they do more dps vs anything they can tank (not 100% true because of how broken fire and poison based damage over time can be).
The disadvantage of hybrids is that they can’t always reliably lifesteal in order to tank bosses and they take forever to kill anything if they have to kite. Also, they require a very intensive play style and require you to have a good feeling about how dangerous the situation is.