Many seem to house rule (corheim forexample) the dagger with -1S. The knife is slightly to good in Vanilla, still -1S doesn't really represent that you fight with a sharp steel weapon.
So I though that you instead ad the following rule:
Short Range – a dagger is a short weapon, and a warrior must come in close on his enemy to be able to strike. therefore a dagger strikes last in the first round of combat. If both has the strike last rule (i.e. Double Handed Weapons) who ever charged strikes first.
Now I don't know if one should keep the +1 to enemy AS, or if this is enough a limit?
This is just an idea, so please tell me what you think.