Wouldn't it be easier to just add the weapons a second time with (Enlarged) or (Reduced) in the weapons setup? If they use it all the time I think this would work for now. At least until someone re-writes the attack system to use JSON's and can be manipulable(sp?) by the Active Mods system. Should there be any verification that the player typed in the damage correct? i.e. Greatsword goes from 1d8 to 2d6 but the player puts in 2d8 Or, would you rather have the tooltip change to show the original weapon damage line and the new weapon damage?
Admittedly, I do that already, and it does work. Invariably, they change weapons on me, or I sunder or disarm them. Two out of five players understand the weapon setup enough to do it without me.
is it essential? Nah.
Just a thought.