We can update the wiki, but this is a touchy thing because we don't want to make wiki edits unless we are 100% sure they are accurate.
According to mojuk though, if i understand him correctly maybe it could say this:
"Fast Shot effectively "trades" a weapon's ability to be aimed, for the ability to be used faster. But it only applies to weapons that can be aimed. Weapons that cannot be aimed (like grenades for example) at eyes or limbs, do not allow any bonus from this Trait."
Is that satis?