I always think it looks better when characters fight with sharp swords on stage, and I work with the actors to sharpen them beforehand. I hate it when they wave around hunks of blunt steel that they know aren't dangerous. The audience can tell.
Now before I continue, my lawyers are telling me that I can't go around telling people to use sharpened props on stage, so I better clarify what I'm talking about post-haste.
I'm really talking here about how to help actors to portray characters in a world where swords are sharp and weapons are serious and dangerous. Too often, actors handle or react to weapons, especially swords, in a way they would never do in the real world. And if the characters don't seem to perceive the weapons as dangerous, the audience won't either.