This is not how it works.
The correct formula is :
Weapon damage x weapon skill x (strength + warfare)
With a mace with 35 dmg base, 30 strength (+100%), 10 warfare (50%) and 10 in 2handed (50%), it gives :
35 x 1.5 x (50% + 100%)
35 x 1.5 x 2.5 = 131.5 (which gives 132 dmg in tooltip)
Went and tested in GM mode.
The stat of Warfare and Ranged is directly shown on your weapon damage when you increase it.
The final damage is weapon damage * (1 + stat *0.5 + weapon talent) * (Warfare/Magic multiplier)
So
100 ranged weapon damage
30 dex 100% damage
10 warfare 50% Physical
10 ranged 50% ranged
gives
100 * ( 1+1 (dex) + 0.5 (ranged) ) * (1 +0.5 (warfare)) = 375 damage
So in a way, weapon talent are actually just increasing dex/str with extra stat bonus. Highest damage will have you go for 10 warfare first on any physical damager
The final damage multiplier (crit, highground) stack additively.
Haven't tested magic.
I can confirm the findings that Stat+Weapon Skill are additive together and multiplicative with Warfare.
One more thing, the rounding is very generous.
The base weapon damage is rounded up to the nearest integer after multiplying each time.
For example, my Crossbow does 12 listed base max damage with 24 Finesse (+70%) , 2 Ranged(+10%), and 2 Warfare(*1.1).
We get:
12 * 1.8 = 21.6, rounds to 22.
22 * 1.1 = 24.2, rounds to 25.
This matches the in-game tooltip of 25.
W/o rounding we'd only have 12*1.8*1.1 = 23.76, which is wrong even if rounded to 24.
The take-away from this math is that weapon ability passives should not be taken before Skill passives.
Stack the stat you want and the Skill passive to max before investing in any weapon ability points.
This seems like a bad design because the Skill points also allow you to learn high level skills and don't restrict the user to a single weapon type.
