Summarizing the Third Century Crisis

[Praefectusclassis]

Jona, you may want to try to get your hands on the 7th volume of the Impact of Empire conferences. It addresses mostly structural and less the military parts of the crisis (whenever, whereever and to what extant it was a crisis).
It has always been drilled into me that it is important to point out that the crisis left some areas more or less untouched. Re: the defense in depth aspect, the Augsburg stone that tells of a Germanic raid that was intercepted on its way out of the empire is a beautiful piece of evidence.