If someone makes their save to disbelieve a shadow weapon, does it still deal sneak attack damage? since it still does 1 point of damage?
i don't see why it wouldn't. shadow spells (and feats) recreate the concept of taking an illusion which is not real at all (ie people who make their saves are not affected at all) and taking a little bit of the plane of shadow to make them more realistic by adding a small amount of real substance to them (ie taking a percentage of real damage from shadow spells if they make their save, or in this case 1 point of damage from the weapon). note it is only talking about weapon damage for the save, any other modifiers would still be added. so bonus for high strength, sneak attack, or if you had some ability to imbue it with special powers (like a paladin can) those would still work normally too.
So, if you were to make a ring of shadow weapon for a rogue it'd be pretty dope.
or if he took the major magic talent to cast it 2 times a day if he is ever captured/imprisoned and has all his gear taken.
I guess that comes down to weighing the ring slots vs limited feats. Still, at will would be nice. However, in the case of the feat, he's "unarmed".