It sounds like they already have too much work without another line (a minor issue they could fix by giving up sleep), so the Tian Xia stuff we might see somewhere in the future, it will be chronicles stuff.
Too early to tell, I suspect, as I don't recall seeing any official statement on the matter beyond "we'll get to those areas eventually".
I have my suspicions on how it'll roll out but I think it's safe to say that however it DOES roll out, Paizo will be doing as much homework as they can to ensure that the route they pick is the best for the company. That is, they're not going to abandon the Inner Sea region for Tian Xia unless they've determined it's popular enough to carry the line.
My personal suspicion/bias is that while the other regions of Golarion will see support, the original setting area will never be abandoned as it supports the widest range of "classic/traditional" fantasy. Personally, while I'm interested to see the rest of Golarion, I don't know that I'm going to wrap-up an existing campaign just to move things there.
Would I use it to provide additional character concepts for "visitor from a strange land" players, trade-route/sailing/pirate campaigns, or even "threats from a foreign land" storylines? Absolutely.
So my guess is that over time you'll see a shift from 100% core setting to some mix of core setting + exotic locale. Popularity (i.e. sales) will determine how much support those exotic locales receive over time.
100% speculation, of course. MAYBE worth 2 cents.
