Feudalism can be simply defined as: 1. fragmentation of political power; 2. public power in private hands; and 3. armed forces secured through private contract.
I find the dictionary much more accurate for defining the word:
The feudal system; a system by which the holding of estates in land is made dependent upon an obligation to render military service to the king or feudal superior; feudal principles and usages.
Or
The social system that developed in Europe in the 8th C; vassals were protected by lords who they had to serve in war.
On the otherhand, none of these are quite adequate when speaking of feudalism as an era in history. This is because feudalism was in a constant state of evolution and existed in several different forms, varying from time to time and place to place in Europe. These were part of a gradual development over a good many centuries. The results at any given time showed various forms feudalism growing side by side, most often developed without any form of or relation to chronological sequence, and thereby can be best described as a partially organized chaos.
While the word "feudal" clearly came from the German, its initial development occurred under the Franks in Gaul. But the institution of royal benefices did not exist under the Merovingian Franks. Such developments did not occur until the Carolingian era with its wide spread confiscations of church lands. Argument as to who was initially responsible for Europe's advancement or decline into feudalism, be it Charles Martel or his sons Pippin and Karlmann, makes interesting history, but I would concede that it has little to with our discussion. As is the case of your reference to Gregory VII.
As far as my statement that the church was a superstate goes, I qualified the statement. I might further add that it was you that first brought up the church's authority over matters of morals and religion. That alone qualifies it as a superstate, without mention of the lands and people it directly governed from time to time.
If I were an advocate for feudalism or monarchism (which I am not), I would be an extreme advocate of mix Ayn Rand's ethics and philosophy with anarcho capitalism as most often defined these days with in the libertarian movement. That is, I would reaffirm Frederick Bastiat's arguments on a never ending availability of cheap land as a counter to John Locke's proviso that so long as "at least where there is enough, and as good left in common for others." If you take the Randian and current anarcho capitalist positions and apply them to the real world, after a generation of Randianism, you would have a mixed monarcho governmental system. After that government would be pretty much not relevant. A quick almost unnoticed switch over to anarcho capitalism would be easy and a feudal monarchist system is what you would actually have.
The best stage to begin bringing this about (at this time), is the Libertarian Party stage. Almost all of the conservative natural rightests, be they minarchist or anarchist, are already on board (they just don't know it). Even the hard core radical left wing anarchists (to include the voluntarists operating outside the party) are already advocating positions consistent with such ideals and need only be brought back into the Party with a program of mutual education. The only real significant opposition will come from utilitarians and Democratic Party leaning Libertarians. But their numbers are currently down, but rising.
As I see it, the Libertarian Party is the future battle ground. So long as no one side wins control, all sides will keep growing. When ever one side wins significant control, Party growth slows down. Should one side take total control, the Party will then die a quiet death. But I do not believe that is going to happen. Thus I see the libertarian movement and the Libertarian Party bringing major changes to the country in a few decades. And then will start the real fight between you anarcho monarchists and us minarcho lefties.:=)
I don't think we need to go into every detail of how this relationship was implemented at different points in history and in different places. Such adaptivity, even if it looks like chaos, it in itself a virtue.
I brought up the Invenstiture Controversy to underline the contentious relationship between the church and the secular world. The Pope could not order the emperor around, and vice versa. At all times the church had authority over the faith and morals, and life/property torts were handled by the state.
If you take the Randian and current anarcho capitalist positions and apply them to the real world, after a generation of Randianism, you would have a mixed monarcho governmental system. After that government would be pretty much not relevant. A quick almost unnoticed switch over to anarcho capitalism would be easy and a feudal monarchist system is what you would actually have.
With Hoppe, I think that we are heading toward anarchy and natural order. Feudalism is a model to keep in mind, because feudalism was the natural order in 5-15 centuries. In a technological society the vassal-suzerain relationship will take a different shape, of course, than in an agrarian society. Most likely we will recognize them as agent-client or employer-employee relationships. But unlike most anarcho-capitalists I believe that monarchies will emerge from anarcho-capitalism, and I believe that the Christian faith will be the central organizing factor of this social evolution.
I don't think any political parties, or even any conscious political effort today will have any bearing whatsoever on the social dynamics in the 21 century.