Edit4: Made it to A10 before it hit me... most of Chieftain's ascendencies don't do much if we're not fitting in warcries... The "cover in ash" can be replaced by a Xoph's Blood amulet as a late-game upgrade for better bossing dps. I'll be re-rolling back to Elementalist. This is the final version I played to endgame in 3.17.

Edit3: Also check out u/Bilbo_Cetero's tricked out Elementalist version.

Edit2: For anyone actually considering this as 3.17 league start, I'm most likely trying a Chieftain Lifetap version (updated 6/2/2022) to make bossing feasible by overcoming sustain/recovery issues. Check the notes on exit strategies in case it sucks. It's still a WIP, and will probably remain a WIP until the middle of 3.17. This is the version I'm rolling with for now.

Edit: Wow this blew up. Summarizing some amazing discussion in the comments:

Other stuff to consider: Razor of the Seventh Sun (big regen = bossing viable with Lifetap??), 2x Replica Cold Iron Points (big dmg), Replica Stampede (trade CDR smoothness for opening up another 6L setup), Aegis Aurora for block, if staying with staff (which could potentially get +5 gems, RIP Realm Ender) there's a recover 2% life/es on block from a Mastery node, and a Chieftain version is possible as well with similar DPS but way better defense.

TL;DR:

• 3.16 ignite changes enabled this build. 3.17 changes to Ignite and Frostblink are a small net buff (~10%)
• Main concept: Elementalist - Shaper of Flames - Frostblink - Ignite Prolif
  • Similar to RF, Autobomber, Death Oath builds (but day 1, 0 gear maps viable)
  • Completely unaffected by Temp Chains, without needing any investment into it
  • Frostblink has huge damage to scale ignite from, and almost no cooldown as long as you blink into and/or out of packs
    • Frostblink's damage is actually so high that I couldn't find any stronger 6L single-target (check my pre-league start build plan POB), so I recently decided to just switch to a much more defensive 1hand+shield setup.
  • I think this build has potential, but I'm too dumb to find/afford it. Plz halp.
• Videos:
  • 3.16 T15 Sulphur Vents (progressing Atlas, 1 RIP)
  • 3.16 Almost naked BA run to simulate league start experience
• POBs:
  • Pre-league start build plan (Updated: accidentally did some POB warrioring from changing build plans halfway through)
  • Snapshot before I attempted Uber Lab (Lvl 85) (the efficient training jewel was purely for the corrupted blood corruption)
  • Current state (Lvl 90)
    • Haven't done Pantheons or Enchants, the worthwhile wants all want multiple gold oils which I can't afford :(
• Budgets to
  • start mapping: 0 (yes it's a real league starter)
  • halfway through yellows and DIY uber lab: ~50c
  • teleport through red maps: ~2-3 ex
  • anything else: idk I'm poor

NOT A BOSSER

• Can do most map bosses or equivalents, including Scourge bosses (timer frozen), up to ~~T15~~ T16 viable confirmed
  • Started struggling around 4 watchstone conquerors and 6-boss maven invitations
  • Probably can't do any of the "real"/"uber" end game content, never tried
  • Bottleneck is no recovery when life/mana flasks run out
    • Bossing DPS is okay, just not enough to insta-phase
  • Probably best to just roll another cheese bosser, e.g. seismic trap (or whatever build it is for 3.17)
• Maybe SSF viable, but probably wouldn't hit red maps comfortably without some uniques. YMMV.
• Built around a shoestring budget, I generally accumulate <5 ex nett per league, so there's probably some expensive influence/jewels shenanigans I don't even know about.

Hello fellow exiles, just wanted to share and get feedback to improve on my 3.16 build. I league started with it, and as a Casual Player™ it's my only toon in 3.16, and one of my only non-minion characters to reach lvl 90, ever.

It struggles with:

• defenses, running T15+/equivalent content occasionally gets 1-shot, especially against tanky bosses with big AOE when flasks runs out.
• Mana, I don't know how else to manage it except through enduring mana flasks, which is a big problem in tanky boss fights. Best to re-roll/skip "Players cannot regenerate life, mana, ES" maps.

Progression:

1. Levelling: Honestly no idea, I just did flameball ignite, there's probably better caster levelers out there.
2. Can start switching over around the end of campaign. Can farm BA super fast for a tabula, but I went into maps just fine with just picked up gear, 5L main skill.
3. Early gear to prioritize, probably want these before attempting Uber Lab, in order:
   1. Any 5L chest OR a 4L Bronn's Lithe (~1c)
   2. Lv 21 Frostblink (~3c)
   3. The Stampede boots (~10-20c)
   4. +2 cold/spell gems staff (~1c without big links) or Searing Touch (worse than +2 staff)
   5. Eye of Malice (~1c)
   6. 6L Bronn's Lithe (cheap off-meta item, ~20c)
4. Late gear to get, also in order:
   1. Cluster Jewel with Fan of Flames (~15-25c) to replace the Ignite Proliferation gem
   2. One-hand weapon with +2 cold/spell gems (to open up the shield slot) (~30-100c)
   3. Some nice defensive shield (maybe recover life/es on block would be best here) (~30-100c)
   4. Eye of Malice with reduced reservation enchant for Grace/Malevolence (~15-50c)
   5. Asenath's Gentle Touch (just for extra pog, prolif works great without it)
   6. +cold/spell levels amulet

Ideal Gem Setup:

• DPS 6L: Frostblink - Cold to Fire - Cruelty - Deadly Ailments - Combustion - Swift Affliction
• CWDT 4L: CWDT - Immortal Call - Void Sphere - Increased Duration
• Single Target Utility 4L: Arcanist Brand - Frost Bomb - Wave of Conviction - Flammability
• Reserves 4L: Malevolence - (Vaal) Grace - Arctic Armour - Enlighten
• Weapon Auto-Cast craft 3S: Purifying Flame - Summon Chaos Golem - Flame Wall?
• Shield Extra Unused 3S: ???

What do you guys think? Can this build go further without blowing up the budget? Should I prioritize other forms of defenses?