In the case of union of Orthodox and Rome, shouldn't all Orthodox churches in the West be put under administration of Rome to keep canonicity, even if respecting ethnics traits, as an "Eastern Rite", as well as all the,Roma churches in Orthodox countries would be Western Rites under that particular jurisdiction?
Meaning that all Orthodox churches in the West would, not become catholic, because they are united, but under Rome directly?
An interesting hypothetical. Personally, I think that it's an open question. IIRC, the territorial bounds of the Patriarchate of the West ended at the end of Europe (the "New World" not having been discovered during the period of the undivided Church). It's not necessarily the case that "the West" automatically includes the Americas unless we recognise the historical first arrival of the Latins as valid, even if they were outside "the Church" at the time. But, at least with regard to the EO, the first arrival of the Russians in North America has hardly settled the matter here, despite what the MP/OCA has to say about it, so why would we necessarily recognise the Latins' claim?
I think this sort of thing would have to be considered in some sort of council. It's probable that the Americas would be included under Rome, but the bounds of that Patriarchate would have to be revised. But if you're going through that much trouble, why not re-visit the Pentarchy? Sure, the historical value of maintaining that structure is what it is, but if it was originally based on the civil structure, why not incorporate other Patriarchates into the world as we have it today? Surely NY/DC are among the candidates in North America for some sort of Patriarchate here? What are the important cities in South America, Europe, and Asia today? Is there a city important enough in Africa to pose a "threat" to Alexandria (I don't know, I didn't think so). Is there a need to keep Oceania separate, or would it be simpler to lump them with Asia?
We can always ask why Rome should get the West before they are "fully rehabilitated"--even if they returned, it would take some time before Orthodoxy really "stuck"--but I don't know how much we can push this issue. There would need to be oversight, but I think the Church would just have to exercise a liberal amount of trust in Rome, and Rome would need to be transparent. I think the trickier issue would be meeting in council and coming up with solutions that make sense. We can't do that on our own as it is.