The Rim in the Rebellion period was an interesting place and a very dull place. I have always imagined sort of like Poland after the collapse of communism.
Whereby, the Sols claim Earth only to find out that the years of Imperial occupation have left their mark on Terran culture by making it more diverse.
Jon's solution of the authencity movement is band aid solution (and a very good idea) but really one would want to explore Terra in more depth throughout the ages.
After the movement of ROM toward the core, Earth went into a long term decline as the riches were moved elsewhere and in the Long Night, it emerged again as an important Pocket Empire.
But, what happened in Milieu 200 to Milieu 1000, what were the tensions and politics on Earth that pushed them into war with the Imperium. Or was it more the revanchist states of Rim that was responsible for the war. Clearly, Earth was a Jewel in the Crown but like the Raj, once the empire left, it left a backward planet unable to compete until a major change...that change being the TNE era (whether you are a Hale heretic, like myself until I see MJD work or MJD, Earth will resurect itself, as an important Pocket Empire).
So the task that can help us is MWM article in Dragon on Luna reprinted by Starlance Enterprises sometime later. And, also some of the voices of the Ancients on the Fate of Terra. But, I don't mind sharing some of my thoughts. Save that Terra/Earth did really play an important role in my MT campaigns where I centred action in the Core worlds of the 3i and just playing MT Journal adventures with my players which were centred in Deneb.