If neither 15 agi or Fiery helps to avoids the majority of CC, then it makes sense to pick the enchant that does the most damage - that's the point of using it as an argument lol.
And the CC's that 15 agi worth of dodge does help against can be avoided at crucial times when you turn into neo for 15 seconds with that bigass button called evasion. At 90%+ dodge during evasion it makes sense to use dual fiery in most circumstances, which contributes over twice the dps that +15 agi enchants do.
We're never going to agree though because I'm looking at it from the PoV of playing wsg objectively and having end product & winning games. Whilst you're looking at it from the PoV of being a midfarmer with wbuffs that drools over percentages on your character stat page - as your signature on this site shows.
For your special case though, fiery loses value when you stack wbuffs relative to 15 agi. Since fiery is fixed dps whereas the crit from agi becomes more valuable when you have double the AP. So yeah +15 agi probably works out well for you and anyone else who stacks wbuffs before a bg.
- Fiery = 4 DPS*0.9225 = 3.7 DPS
- Lifestealing = 140/60 = 2.330.84 = 1.96 DPS
- 15 Agility = 151.5 = 22.5 AP /14 = 1.6 DPS + 2% Crit over 60 DPS = 1.2 DPS = 2.8 DPS * 0.6 = 1.68 DPS
- Crusader = 100 AP*1.5 = 150 AP/14 = 10.7 DPS/4 = 2.675 DPS * 0.6 = 1.61 DPS
Bad use of equals...I know
That's the dps on a typical bear druid. Change the 0.6 multiplier on 15 Agi and Crusader based on the targets armour. (if a target has 25% mitigation, change it to * 0.75). I explained my reasoning behind why I mainly care about dps on a druid in my previous post.
Also, since offhands miss more, 15 agility has the advantage of providing stats that benefit your mainhand hits and sinister strikes along with some dodge % even when your OH doesn't hit (whereas the other enchants can't proc on a miss). But as you can see from the calcs, it's still going to be way below fiery dps even factoring that in.
If I'm killing a hunter or rogue FC which inevitably are common in pugs due to their overrepresentation, I'll
sometimes switch my offhand for a +15 agi assassins blade just for higher dodge chance. I don't want to eat some freak clip or gouge with evasion up but it really depends on how much hp the target has and who else is around.
Paladins, warriors, other hunters, shamans, mages all have tools which can change which ench is best in the situation.
tl;dr get both, make switch macros and pay some attention until it becomes second nature to just switch on the situation. If you stack wbuffs, elixirs and all that jazz then just camp +15 agi.