DW, if all home owners were armed and were legally allowed to use them, this could open up a real can of worms, for example:
You want to get 'rid' of someone, so you envite them into your home, shoot them, phone the police and 'tell' them that they were trying to rob you.
Or, your tired and half asleep, someone who is not a burgler comes into your home, maybe it's a carer or a family member, it's dark you think your getting burgled, you shoot and kill an innocent person..
You son/daughter young family member gets into trouble, they gain access to your shotgun and all kinds of trouble ensues.
Your young family member has a party, gets drunk, starts mucking about with the gun, it goes off, a friend gets killed.
In short, I agree that we should have more powers to defend ourselves against burglers, I just don't think this is it.