And it's also a slippery slope as well, if you allow firing a weapon in pursuit: how long can you pursue someone, and how far?
Unless you can prove someone was actually in your house, he (or his heirs) can claim that you attacked him on the street, maybe mistaking him for someone else, etc.
Castle doctrine is for castles, and even inside the castle it isn't limitless.
Still, this guy should get a medal, not a sentence.