Right off the bat (pun intended). Something that normally has (STR + 2)P damage gets calculated out. Let's say it gives 7P damage. This would in turn translate to 3.5S damage, which gets rounded up to 4S.
The next problem that could arise is that Swords are not meant to be used with their flat side. They chance to break could be increased.
True, I think on a critical glitch they should receive damage to their AP or Reach value (a topic covered in Run & Gun.
I agree that the stun damage rules are ridiculously complicated and weird. Even for shooting someone, it doesn't make a whole lot of sense. I simply cannot imagine how shooting someone could result in stun damage. I'd rather just have them shoot someone in the foot and roleplay the incapacitation if that was necessary.
My players have a habit of pistol whipping every surrendered enemy or civilian senseless before progressing, which is good practice but feels a bit lame. They basically say "I whack him in the head until you tell me he won't get up anymore in the next ten minutes".
What I want is to instill some (small) fear of repercussions from excessive blunt force head trauma, since you certainly could not knock a hundred people unconscious without risking one of them dying from the injury.
To that end, my proposed house rules:
1. No more ranged-weapon called-shot stun damage. I'm not even going to consider unusual cases like a beer bottle or a crate until it comes up.
2. When meleeing someone, declare a stun attack. -2 penalty if it's conceivable you could prevent it from being lethal (e.g. clubs), -4 if it's clearly pushing the limits of the weapon (knives, katanas).
3. After the declaration, you can choose to subtract any amount of additional dice from the attack.
4. After the declaration, you can choose to neglect all overflow damage from net hits.
5. Total damage is halved and turned into Stun.
6. Glitches result in halved Physical damage.
7. Critical Glitches result in full physical damage with normal net hit damage overflow (disregarding your earlier choice) and the weapon is damaged in the attempt.