No really, normal one-handed weapons which are not daggers do a great deal more damage than daggers do. Making them cost 2 AP for any reason would be completely overpowered. I think that special abilities are supposed to take the AP cost of the weapon into account, so that part should happen. Maybe that's not working yet? I haven't checked.
You can find weapons and helmets and maybe other things with +1 WotW, so it's not necessarily 15 AB points.
Again, it is an interesting idea, but it has to be approached carefully.
I did make an idea to differentiate bows and crossbows, which was to reduce the effective range of Crossbows by 5m, although thinking about it now, I don't know how that would work with skills and special arrows, though. No one replied, indicating that they either had no opinion or thought it was a bad idea.
