On a lighter note, I found this old AH timeline
from 2010 (who'd've thunk?) which deals with almost the exact same theme as this TL: what if Rome united, and China collapsed, and the respective roles of east and west swapped, and all that fun stuff - could possibly be a source of inspiration, kickstart this timeline back to activity, perhaps?
(Though I'm not sure about how thin the line is on here between plagiarism and inspiration: given the kicks I've seen happen sometimes...
Two maps from the site (not mine, the author's of course), set near the end of the 17th century (the last ones on the timeline: it seems to be unfinished):
(Speaking of religion, the author decided to go with the choice of a continuing-pagan Rome, and a Christian/Buddhist-syncretic China: come to think, that would actually be a pretty interesting choice - like Christianity in the middle East OTL, the religion would "regather" it's strength in another region, also coincidentally the region that would eventually dominate the world. OTOH, as cool as that would be, it does makes me wonder about the ideological inclinations of the author: although not same lazy Eurocentrism evinced by the at-least-envisionable-AH of a dominant China, it is a mite Christian-centric, with part of the inherent logic here being paganism/polytheism = backwards, decaying empires, Christianity/monotheism = advanced, modern and "scientific". I guess it would be possible to read this as "progressive" in one way - hey, it's not because of some inherent racial advantage Europe has that catapulted it into modernity: but merely Christianity,. which isn't even European in the first place! If China had it, they too would have been rich and modern instead - how enlightened! Still, it is
a fun idea, in spite of - to me, anyway - some slightly dubious assumptions about history
(The world in the 17th century: apparently Japan had still conquered Korea - the author having really stuck with the whole "parallelism" thing to the end - though the Chinese states are starting to diffuse around the globe; some of the European states, outside of Rome, seem to have their own wee colonies, but not as large as the Chinese ones. The "Jurchen" empire is apparently an Ottoman-analogue, it having conquered Beijing - and with it, the ancient Chinese empire - in... 1453.)