Level 81 Crit Elemental Hit Raider^3.21

Notes

Gems Needed
A1 - Elemental Hit x2, Steelskin, Onslaught, Dash
A2 - Trinity x2, Elemental Damage with Attacks x2, Summon Skitterbots, Power Charge on Crit
A3 - Grace, Second Wind, Sniper's Mark, Inspiration (Library) x3, Hypothermia (Library)
A4 - Chain, Barrage Support, Mark on Hit
A6 - Hydrosphere, Elemental Weakness

Rush Elemental Equilibirum and Point Blank for early damage boost for leveling

Don't swap into barrage until after getting Avatar of the Veil and refunding the EE/Avatar of the Hunt points or it'll brick your damage

Uniques
Widowhail looks like a dream starter bow for Elemental Hit because we don't rely on the bow's damage stats at all. I'm not a big fan of quill rain because of the damage penalty and the fact that it is in high demand for other bow starters.

Asenath's Mark divination card is back so that's a nice target farm for QoL
https://www.poewiki.net/wiki/A_Note_in_the_Wind

Drop Mark on Hit once you get Asenath's. Hydrosphere is just for the power charge/onslaught generation, eventually I craft a hunter/crusader chest for power charge generation and extra curse.
At that point we can drop hydrosphere and power charge on crit and add elemental weakness and enhance. Inspiration just helps the mana cost

Jewels
Lethal Pride in the Wind Dancer socket for as much double damage chance as you want to spend, this also gives all the strength we need
Watcher's Eye - % Additional Chance to Evade with Grace, can upgrade to a 2 mod with Precision later

Ascendancy
Way of the Poacher > Avatar of the Slaughter > Quartz Infusion > Avatar of the Veil. You can do Rapid Assault and respec but I personally found it too costly at league start.

I played 3.20 with 3 and 4 base projectiles and the chain/AOE

Deadeye:
I think the addition of extra projectiles on the tree makes Deadeye less attractive. In order to go Deadeye, you need additional spell suppression on gear and are basically forced to roll 50% avoidance boots or give up jewel slots. Asenath's makes
Focal Point somewhat redundant and you can't easily get the full benefit of Far Shot the way that Tornado Shot works. Deadeye will also need the Corrosive Elemental notable and mastery for 18% exposure, unlike Raider's instant 20%.

Slayer:
On the flip side, the extra projectiles on the tree is a big plus for Slayer. If you are looking to just league start and switch to another build, I would say Slayer with AoF is probably the better choice. The Overwhelm ascendancy point will offset the
lack of brittle and Slayer culling is really strong plus the Marked for Death cluster had a slight nerf.

3.21 Changes

Prismatic Burst - possibly a good damage boost while leveling. Not sure how the element selection RNG would combine with EH.
Manaforged Arrows - EH mana cost is naturally high without Inspiration and mana cost reductions, maybe there's some cool synergy that's possible

Vengeant Cascade - projectile return was reworked, I don't know if there's some crazy interaction we can use with Tornado+Arcanist Brand to massively boost single target the way Hydrosphere used to work. Anomalous barrage support
gives +2 pierce so that is something I'll be checking out.

Crucible trees - we can replace The Interrogation with a Crucible tree on our bow, this will likely be an endgame min/max thing and not expected at league start.