Heller only dealt with the issue of a man who wanted to be in possession of a firearm within his home, so that's the only issue the Court decided. It was clear that it was not ruling on any other issue. Court all over have been jumping on that, and taking the position that because that was the ruling in the case, that the decision has no meaning outside the home.
I think the flaw in that argument is another issue that Heller did decide, and which I think is really the bigger Constitutional issue. The Court explicitly held that the "selective incorporation doctrine" by which "substantive due process" is implemented, is out the window. What that doctrine meant was that only those parts of the Bill of Rights which the Court had specifically (and selectively) stated applied to the states did apply to the states, and all the rest did not. Originally, and for a long time thereafter, the Bill of Rights was taken to be a restriction on federal power, since it is clearly written to constrain what Congress can do. But later, the Court took the "due process" clause in the Fourteenth Amendment (which is aimed specifically at state governments) to mean that states could not deny citizens certain "selectively incorporated" elements of the Bill of Rights.
What Heller decided is that all of the Bill of Rights applies to the states, unless for some reason the Court carves out an exception. That's a really big change.
So where I think the courts have gone wrong is by applying "selective incorporation" analysis to the results of Heller. They are taking the position that citizens' rights that the Supreme Court have not expressly held to apply to the states are still exclusively matters of state law. But Heller said the entire Bill of Rights applies to states, without any exception (since the Court has never, as far as I can recall, stated that any particular aspect of the Bill of Rights does not apply). So location just plain don't matter, subsequent to Heller, because if there's a federally recognized right to self-defense, it's an expansive right unless the Court has expressly limited it.