Alright guys here's a theory craft build for 3.5.
Cospri's Champion Freeze Pulse/Glacial Cascade
This is a rich boy build, 100% NOT a league starter. Why is this build expensive?
*Corrupted +1 Power Charge on Starkonja will definitely cost you some money and it's fairly important to the build.
*6 link Loreweave. Build becomes a bit clunky to use if you don't have the 6 link body armour though any 6 link body armour will get you started even a Tabula Rasa.
*Dual Wield Cospri's Malice. A tier 1 rare item that is very likely to go up in price in the new league. And this build uses two of them.
*Pandemonius necklace is fairly expensive early into the league.
*Elder ring with Warlords Mark curse on hit and other good stat. Probably the best rare in that build I have, you will not be finding a rare that good so you are going to have make up the resists somewhere else (build is already resists starved).
*Watcher's Eye with +critical chance from Hatred aura. Very important to the build for consistency and damage, this will cost money as well. Luckily it's only a 1 property Watcher's Eye and the price can go even higher with a double or triple Hatred eye.
*There are two places that you can place Inspired Learning by reallocating some points though my build doesn't use it.
The first question someone is going to ask is... why Champion for this type of build? Why not Assassin? Assassin is the superior crit ascendancy however, with Assassin you are going to have Accuracy issues. Without good accuracy, a cast on crit build is very bad and thus most Assassins generally have to use a Lycosidae shield and only one Cospri's Malice. With Champion, I have 100% hit chance on enemies which is insane. By using the Watcher's Eye jewel, Critical strikes gem, 7 power charges and crit on the tree, I can easily attain near capped crit. Plus Champion has much better defensive bonuses AND I don't need to use Tombfist to have Intimidate on my character.
Next are the item/skill choices:
Starkonja: This item gives everything you would need. The +60 Dexterity is essential because the Cospri's Malice has a high Dexterity requirement, it gives you global crit, attack speed and some extra bonuses. This is IMO best in slot for the build.
Loreweave: To be honest any body armor would do here, I would even say a good rare with +% crit to attacks affix might even be better. But Loreweave is the save, solid option and it's hard to go wrong with it.
Pandemonius: Gives Blind, Chill and 20% cold damage penetration... excellent for the build all around. You can use any amulet you want, a rare amulet would also work just get some critical multiplier on it.
Mark of the Shaper: A huge damage bonus to the build and I was going to be using an Elders ring anyway for the Warlords Mark curse on hit. It just makes resistances trickier to manage.
Watcher's Eye : Hatred gives +% chance to crit is insane for the build.
2 First Snow: This is for mapping, replace with the 2 jewels for Glacial Cascade instead for more single target.
Blade Flurry: Blade Flurry is the melee attack of choice to trigger the spells. Blade Furry has a lot of attacks in its animation as you are channeling the attacks, it has range so you are safer than usual and Faster Attack works very well with it. You can also use Cyclone but Cyclone is less safe and Cyclone is more used for something like Discharge builds.
Frostbomb: To reduce cold resistances for single target.
Warlords mark on the Elder ring for sustain and endurance charges.
Blood Rage for attack speed and frenzy charge generation.
Lightning golem for attack speed.
Herald of Ice for clear.
Whirling Blade for mobility and turning on Fortify.
How does this build work?
Some of you are probably new and are wondering what's going on with this build. This build revolves around the Cospri's Malice unique sword. This sword triggers socketed Cold gems on melee critical strike chance. This is similar to how the Poet Pen works only Cospri's has more restrictions. Because of this you require a Melee attack skill AND high critical strike chance. This means that you have a chest slot open for cast on critical set up as it has synergy with Cospri's Malice. Cospri's Malice also has a high Dexterity and Intelligence requirement to wield. So to even make the build work we need high Dexterity, high Intelligence, high Critical Strike chance and high accuracy. With the Champion Ascendancy I get full accuracy and from the tree/gear I can get my remaining crit in addition to running the Diamond Flask. I naturally get all the Intelligence through my pathing and by wearing a Starkonja and having a +30 Dex node on the tree or on the gear I can wield the weapon.
With one attack, I am able to fire off the gem in Cospri Malice 1, Cospri Malice 2 and the gem in my chest which is linked to cast on crit and a melee attack (in this case Blade Flurry). So per ATTACK I am unleashing 3 spells at once. So how many attacks am I doing per second? With full buffs I am doing around 8 attacks per second which is a bit overkill as the Cast on Crit gem has a 0.15 second cooldown that means that I need under 7 attacks to get maximum utility. However I have some extra attack just to have some cushion in case I need to drop some attack speed to get my stats in order. HOWEVER, if I manage to get Cooldown reduction on my Boots and Belt (via Elder/Shaper mods) I can lower the cooldown of cast on crit gem to something like 0.11 which means that at 8 attacks I am still being optimum. If you can get to around 8 attack speed consistently then you can drop the Faster attack speed gem for a Hypothermia gem for more damage.
So what's the damage like?
It's hard to tell what the damage is just from PoB so here's the breakdown (with all bonuses up during bosses except Frenzy Charges/Endurance Charges).
Single hit from Freezing Pulse in Weapon 1: ~85K
Single hit from Glacial Cascade in Weapon 2: ~64K (with the jewels this will do much more damage but that's not accounted into the damage)
Blade Flurry DPS: ~85K
Single hit from Freezing Pulse in Cast on Damage set up in Chest: ~74k
Multiple the single hits by 6 for the times I am critting in one second accounting for the cooldown of 0.15s on Cast on crit: 510K + 384K + 444k + 85K (Blade Flurry which already accounts for the attack speed):
Roughly 1.4 million Shaper DPS when all buffs are up. And the build has great clear as well.
*Variations
*For only 3 more points, you can have 2 curses on the build. The 2nd curse I would get is Frostbite though it's very difficult to put that into the build.
*There are two good places to put Inspired learning, near both of the Power Charge nodes on the left/right side of the tree.
*You can easily change this build into a Cospri's Malice build by changing the Necklace to Voll's Devotion and the chest to Voll's Protector, swapping Blade Flurry with Cyclone and Power Charge on Crit with something like Cold Penetration/Hypothermia or even Critical Multiplier. And of course replace the Freezing Pulse with a Discharge skill within the Cospri's Malice.
*You can use something similar for Poet's Pen as well and that's probably the cheaper/more effective method of this type of build. You just replace Blade Flurry with Power Siphon since you no longer need to be melee and Power Charge on Crit with Hypothermia for more damage. Though if you are going Poet Pen there are other classes you can do for better result like Elementalist and other spells like Arc or Volatile Dead.
Here's a visual look at the build (keep in mind it will be stronger than this in 3.5):