I'm with Sancta on that one. If you read Supernatural (or inhuman, etc) Strength it says that it simply increases the stress dealt. Off-hand weapons training adds half of the weapon bonus. They're independent from each other because they effect two different parts (the stunt working on the weapon bonus, and the power adding to the end result).
A valid point. I am inclined to agree if for no reason other than game balance.
I do wish however, when "Our World" lists weapon values for monsters they didn't include bonuses from stunts or strength in the weapon value. It should have been listed or denoted in a fashion to make it clear what was stress inflicted and what the weapon value was.
My example above used the Loup Garou statblock.
In said stat block the Loup Garou attacks with a weapon:6. This is a rresult of Claws - 2 Strength 4. If those are both considered weapon value then I can see how one could easily interpret strength to count as weapon value and therefore grant the bonus.
It will likely vary from table to table, how that stunt is used.
I intend to list varied ways two weapon fighting is executed and why players and GM's alike may be inclined to have strength work on this stunt.
D&D/AD&D- once appropriate meausres are taken or appropriate penalties to attack rolls (accuracy) an additional attack was allowed with full strength and magical bonuses.
D&D3.X/the other d20 systems of that era - same as above (caveat: half the strength bonus of the character was applied to off hand attacks [this is in my opinion what inspired this stunt in DFRPG]), in fact one could even gain an additional off hand attack.
Old World of Darkness suplements- off hand attacks gained full benefit from damage boosts, but suffered accuracy penalties. (or a dice pool penalty)
Many games do not allow multiple attacks at all. Therefore two weapon fighting is flavor rather than mechanical in nature (Mayfair/West end systems (Star Wars/DCHeroes), mechwarrior, Marvel Roleplaying game (circa the 90's).
DFRPG: no multiple attacks, but wizards are very powerful and this stunt helps min/max and attempt to bridge the gap. I could see how people would want two weapon fighters to deal more damage. (perhaps even to interpret the weapon value of stunts and strength to stack)
Game balance wise I am torn honestly. I do believe multiple attacks would work to the detriment of the game. Everyone talks about action economy and I assume this is what they mean. I do see how melee fighters or fist fighters or gunfighters may want an edge (based on character concept and style of course) to get them closer to the damage output of a spellslinger.
