Neonchameleon
Legend
I'd like to break this down into two parts:
1) In the real world can a dagger be just as deadly as a greatsword? I think the answer is yes it can. Hit the right spot on person with a sharp blade no matter how big the blade is and that person will die.
And a syringe full of air can be utterly lethal.
2) In an rpg is it a good idea to make a dagger just as deadly as a greatsword? I think the answer is not really. Unless you want to get into the granularity of weapon vs. weapon, weapon vs. armor, weapon vs. size of creature and so on the details of this will just bog down the game and the role-playing. You can still create options that improve the daggers effectiveness in combat and make it an interesting choice for a character without making that character useless.
Indeed. But a dagger was a third rate battlefield and duelling weapon. You need to make longer weapons faster for one thing (yes, I'm serious. Reach means you hit first, and a flick of the wrist on a sword can move it very far). And probably go down to Gurps-granularity. Also you need to take into account that the best way to parry a dagger with a sword is at the wrist - the hand needing to move that much further from the dagger wielder than the swordsman.