Dagger-thief

Realistically and comparatively I think a sword should do more damage than a dagger.

But, I do feel that Thieves seem more appropriate wielding a dagger.  Thieves back-stabbing with Shortswords seem inappropriate to me.  I would be completely fine with incentivizing a dagger by giving the Thief a starting ability allowing him to do 1D6 with a Dagger.  This basically just saves him 1 weight and incentivizes him to stick with what I feel is normal fantasy color.

the d6 weapons only weigh 1 as well. it is nothing besides color wanting to have a dagger instead of a short sword. the reason i see taking a dagger over a short sword is that it is smaller and therefore probably easier to conceal.

Like in AW, the names associated with damage are largely flavor. The damage:weight:cost pairing is a little more important, since there's an economy there. There's also what weapon types are available to what classes, which is largely flavor plus a bit of 'balance' in the sense that the wizard shouldn't have as awesome of a weapon as the fighter.

You'll notice that in the fighter's signature weapon and in the top tier of standard weapons, adjectives are all that's applied. Feel free to do that if you want to, to treat a weapon as another type. A Loadstone Dagger might be more like a shortsword, in terms of stats.

I don't really care at all what weapons do in the real world. This is Dungeon World!