Exploring it a bit, we could see something like this:
Vial of a Chilling Substance: A chilling substance that can be used to coat weapons with, granting them a chilling strike and 5% bonus damage done as cold damage. Enemies that are hit are chilled along with a 10% chance of being frozen. 3 Resource Cost is added to non-resource generator skills coated with this substance. Resource generated is decreased by 15% if applicable.
Vial of a Burning Substance: A burning substance that can be used to coat weapons with, granting them a burning strike and 5% bonus damage done as fire damage. Enemies that are hit have a 35% chance of being set ablaze. 3 Resource Cost is added to skills coated with this substance. Resource generated is decreased by 15% if applicable.
Vial of an Electric Substance: An electric substance that can be used to coat weapons with, granting them an electric strike and 5% bonus damage done as lightning damage. Enemies that are hit have a 10% chance of getting stunned with paralysis. 3 Resource Cost is added to non-resource generator skills coated with this substance. Resource generated is decreased by 15% if applicable.
Vial of a Toxic Substance: A venomous substance that can be used to coat weapons with, granting them a venomous strike and 5% bonus damage done as poison damage. Enemies that are hit have a 35% chance of being poisoned. 3 Resource Cost is added to non-resource generator skills coated with this substance. Resource generated is decreased by 15% if applicable.
Vial of an Explosive Substance: An explosive substance that can be used to coat weapons with, granting them an explosive blow and 20% bonus damage. Projectiles no longer pierce. 13 Resource Cost is added to skills coated with this substance. Resource generated is decreased by 80% if applicable.
Vial of a Plaguing Substance: A plaguing substance that can be used to coat weapons with, granting them a sickening strike and 3% bonus damage. Enemies that are hit have a 20% chance of dealing 10% less damage and taking 5% more damage. 7 Resource Cost is added to skills coated with this substance. Resource generated is decreased by 50% if applicable.
How to apply coats?: You can apply coats, either individually or collectively, using the skill slots on your skill bar. This way you could choose to either apply your skill bar with a single coating affect, or apply different coating affects to different skill slots to suit your preference and build. Pretty much when you’re choosing a skill to set to a skill slot, you could also choose to either apply a coating effect to the skill slot or remove one. Once a coating effect has been applied to a skill slot, whatever skill you set to that skill slot would gain the effect of the Coat also set there.
For example let’s say we have someone who set their skill bar with the following coating effects:
1: No Coating
2: Chilling Coating
3: Plaguing Coating
4: Chilling Coating
5: No Coating
6: Explosive Coating
Now let’s take Multishot (a skill that would likely be among a Diablo Archer type class’s skillset), and set it to the 1st skill slot. While there, Multishot would have no coating and such no added effect. However set Multishot to the 2nd skill slot and the skill would now chill enemies with a small chance to freeze them also, albeit at an additional resource cost; or set it to the 6th skill slot and Multishot would now explode when it hit enemies dealing significantly more damage but also costing more resource. And this would apply for almost all skills.
A minor note, while different coating effects can stack, coating effects of the same coat won’t stack. So you could use a coating affect of fire and ice on two different skills and apply both of the effects on the same monster. However you won’t be able to apply and stack additional plaguing coating effects on the same monster, even if you use two different skills with the plaguing coat. This would also apply for multiple hunters fighting together (so 5 Hunters wouldn’t be able to stack 5 different plaguing effect on the World Boss).
Admittedly there are some flaws with the concept. One such flaw would indeed be Traps. However the issue there imo lies mostly whether the traps for the Hunter would operate similar to Diablo 2 Assassin’s traps (Mystical Constructs that draws strength from magic to operate and attack), or Diablo 3 Demon Hunter’s Sentries (Physical Devices that are possesses gears and working mechanisms and mostly uses weapons for attacking with instead of magic). If the Hypothetical Hunter class uses traps that are magical based, then yeah it wouldn’t really work that well… Well it would still work, it’d just be weird from a lore perspective. However, if the traps are physical based with little magic reliance in terms of operating and/or weaponry, then it would be fine imo.