Disagree with your analysis of Rome. By the later Empire there was much less local feeling between the former nations and against the Empire, although there was less unity between the two halves of the Empire. Even the near neighbors felt themselves to be part of the Roman world, and tried to take refuge behind the frontiers when the alien Huns attacked them. Your idea is also disproved by the fact that the only pre-imperial nation to resume its independence was Britain, which was cut loose by Rome, rather than seizing independence.
The Empire died because its economic system, based largely on expansion to create wealth in human slaves, failed when expansion ceased. Expansion had to cease because the Empire had become impossibly large to administer. Having to expand to exist, and being too large to expand, meant that its end inevitable.
My point was not that they wanted to be free from Rome but rather they wanted the benefits of the empire but they were not committed to the empire.
So much has been written about the problems the legions had because they eventually became dominated by foreign troops, I don't need to repeat it here. The same problems, however, existed in all areas of the empire. Those administering the empire no longer were concious of building a better empire. In large part I think because they were not in fact "Roman".
Who in the last 3 centuries sought to "find Rome in bricks and leave her clad in marble"?