Ah, ha! There is the suggestion that light weapons should do as much damage! :D
+1 damage is mechanically comparable, but I would only use it as a temporary option until I could come up with something more fitting to the flavor of light weapons as +1 damage is lazy design.
By my RAW calculations and Homebrew calculations fighting styles are worth about +10% DPR. Dueling accomplishes that.
Dueling isn't a bad choice, the lack of a feat or talent to follow it up with is the problem. GWF is only giving 7-8% more DPR, but that's because the DPR of the fighting style is so strong from GWM. Dueling needs a comparable feat.