This is a basic outline for what I'd personally like to see as the next physical ranged job. I don't have any art mockups or anything but I've hashed out what I think could be a fun rotation and ability suite.
Gambler (GAM)
Role: Phys Ranged DPS
Weapon: Twin Pistols
Background: Masters of a pistol-focused fighting style, "Gambler" is the name given to a rare breed of duelist who fights not for honor, wealth or glory, but purely for the thrill of wagering one's own life in mortal combat. The signature technique of the Gambler is the Phantom Die, a mysterious magic artifact which, when imbued with the Gambler's own aether and rolled, grants them a variety of magical boons depending on the result.
Between their skill at marksmanship and their singular willingness to take any risk purely for their own amusement, few can match a Gambler in combat. Though Gamblers appear to be reckless wildmen with a death wish to outside observers, those skilled in the art know that "luck" is not some capricious whim of fate, but something which can be manipulated and controlled. When victory is not in the cards, don't fold. Cheat.
The concept of the Gambler's playstyle is that you can roll a magicked die to get one of 6 random buffs which then alter your rotation in minor ways. But Gamblers don't leave everything up to chance, they are also expert cheaters. By building up your "Luck Gauge" through basic attacks you can then spend the gauge to manipulate your die and probability itself.
Gambler is overall based a lot on procs and RNG results which then affect your optimal next button, but it is tuned in such a way that the various buffs and procs should more or less average out. It's not so much about winning/losing as it is about adapting to the results you get. Playing the hand you're dealt, in a sense.
I went with Phys Ranged using Twin Pistols because I think it's an aesthetic niche that isn't covered by the existing jobs (Machinist's gun is distinctly different and the job is more focused on gadgets overall) and the concept of playing with probability feels better suited to a job that doesn't have to worry about casting or distance. I also think the aesthetic of Aiming gear in general is suited to a gambler/duelist style character.
I felt that a dice or card-based weapon would be hard to represent visually, and the game already has a "card user" job in the form of Astrologian. Instead I decided to essentially combine Gambler with Gunner into a single job that incorporates elements of both.
Here is the list of actions. Unless otherwise stated, all actions are instant cast, weaponskills (GCDs), 2.5s base recast, 25y range, and have no cost.
Basic Single Target Weaponskills:
Shoot - Deals 200 potency damage to target.
* Increases Luck Gauge by 5
* 50% chance to proc Gambler's Mind, allowing one use of Long Shot or Wide Sweep (30s duration)
* 50% chance to proc Gambler's Eye, allowing one use of Dead Shot or Dead Sweep (30s duration)
* 50% chance to proc Gambler's Spirit, allowing one use of Crack Shot or Clean Sweep (30s duration)
(Note: One use of Shoot can proc any combination of these buffs, including all 3 at once)
Long Shot - Deals 280 potency damage to target. Require's Gambler's Mind.
* Increases Luck Gauge by 10
Dead Shot - Deals 280 potency damage to target. Requires Gambler's Eye. Grants Dead Eye.
* Dead Eye effect: Next weaponskill will be a direct hit. 30s duration.
* Increases Luck Gauge by 5
Crack Shot - Deals 310 potency damage to target. Require's Gambler's Spirit.
* Increases Luck Gauge by 5
Basic AoE Weaponskills:
Sweep - 120 potency to all targets around user. 5y radius. AoE version of Shoot.
* Increases Luck Gauge by 5
* 50% chance to proc Gambler's Mind, allowing one use of Long Shot or Wide Sweep (30s duration)
* 50% chance to proc Gambler's Eye, allowing one use of Dead Shot or Dead Sweep (30s duration)
* 50% chance to proc Gambler's Spirit, allowing one use of Crack Shot or Clean Sweep (30s duration)
Wide Sweep - Deals 150 potency to all targets around user. AoE version of Long Shot. Require's Gambler's Mind.
* Increases Luck Gauge by 10
Dead Sweep - Deals 150 potency to all targets around user. AoE version of Cheap Shot. Requires Gambler's Eye. Grants Dead Eye.
* Dead Eye effect: Next weaponskill will be a direct hit. 30s duration.
* Increases Luck Gauge by 5
Clean Sweep - Deals 180 potency to all targets around user. Require's Gambler's Spirit. AoE version of Crack Shot.
* Increases Luck Gauge by 5
Additional Weaponskills:
Bullseye - 580 potency damage to targets in a straight line, 50% reduced damage after first target. 30s GCD cooldown, 2 charges. 1.5s cast time.
* Increases Luck Gauge by 10
Trigger Happy - Deals 280 potency damage to target. 1.5s fixed recast. Requires Hair Trigger. Consumes a stack of Hair Trigger on use. (see below)
* Increases Luck Gauge by 5
Trigger Crazy - Deals 140 potency damage to all targets in a frontal cone. 1.5s fixed recast. Requires Hair Trigger. Consumes a stack of Hair Trigger on use. (see below)
* Increases Luck Gauge by 5
Roll actions:
Phantom Roll - oGCD. Allows for the use of 1 of 6 random buffs. The buff you roll is stored and can be activated with the separate action "Payout". 20 second cooldown. Can only be used in combat.
Payout - Executes your currently stored Phantom Roll buff. Only one buff can be stored at a time, and using Phantom Roll while a buff is already stored will overwrite the current buff. 1s cooldown.
Potential Roll results:
* The Cup - Increases the potency of your next 3 weaponskills by 100 (50 for AoE actions).
* The Coin - Grants 4 stacks of Hair Trigger. 60s duration. Hair Trigger can stack up to 10.
* The Heart - Restores 1 charge of Bullseye.
* The Rose - Grants 50 Luck.
* The Sword - Grants 15% GCD haste for 16 seconds. (can be stacked up to a max of 60 seconds)
* The Skull - Your next weaponskill hits 5 times, with each hit doing 40% normal damage. 30s duration.
(All results have a roughly equal chance of occuring.)
Luck Gauge Spenders:
Reroll - oGCD. Rerolls your currently stored Phantom Roll buff. Will not give the same result twice in a row. 10 Luck Gauge cost. 1s cooldown.
Hot Hand - oGCD. Deals 150 potency to target and all nearby enemies. 25 Luck Gauge cost. No cooldown. (Note: intended as dump for gauge overflow)
Hot Streak - oGCD. Your next Shoot or Sweep will proc Gambler's Eye, Mind and Spirit with 100% chance. 20 Luck Gauge cost. 30s cooldown, 2 charges.
Loaded Dice - oGCD. Your next Phantom Roll is guaranteed to be The Skull. Also instantly restores 1 charge of Bullseye. 20 Luck Gauge cost. 90s cooldown.
Jackpot - oGCD. Immediately grants all Phantom Roll buffs simultaneously. 50 Luck Gauge cost. 120s cooldown.
Additional Cooldowns:
Ante Up - oGCD. Increases Luck Gauge gain of your next 5 weaponskills by 10. 120s cooldown. 30s duration.
All In - oGCD. Your next Phantom Roll will produce an enhanced buff, but you cannot Reroll the result. Rerolling will result in a normal, un-enhanced buff. 60s cooldown. 20s duration.
* Gold Cup - Increases the potency of your next 3 weaponskills by 150 (75 for AoE actions).
* Gold Coin - Grants 6 stacks of Hair Trigger.
* Gold Heart - Restores 1 charge of Bullseye and increases potency of your next Bullseye to 730. Buff duration: 40s.
* Gold Rose - Grants 75 Luck.
* Gold Sword - 15% GCD haste for 24 seconds.
* Gold Skull - Your next weaponskill hits 7 times, with each hit doing 40% normal damage. 30s duration.
Non-Rotational Bonus Actions:
Bluff - Reduces damage taken by self and nearby party members by 10% for 15s. Does not stack with Tactician/Shield Samba/Troubador. 90s cooldown.
Reel - Dash to target enemy. 40s cooldown, 2 charges, 20y range.
I haven't done any specific balancing against the existing jobs, so the potency numbers are only meant to make sense relative to the other Gambler actions, to give an idea of how the job is meant to play.