Doesn't make sense for the USSR to hold more land than in our timeline, considering they pretty much kept to their own business in the FO timeline, and China was the expansionist instead.
So it doesn't make sense for Romania (other countries as well to be part of the USSR. Even more than that it doesn't make sense for Romania to be united with Moldova, while being part of the USSR. That is just as impossible as dividing a number by zero. Sure, they would probably be united in 2077 but only if they were both independent prior to the union. IF Romania was indeed part of the USSR in the FO timeline then so should be Yugoslavia... however we can see that Yugoslavia is split, somehow. A revolution (in order to split the country) makes no sense while being part of the USSR. Not to mention that Croatia seems to be part of the EC. The communist world wouldn't allow a part of it to just jump ship to the "enemy".
Oh, I see. And yes, thracians proper would indeed be influenced a lot by greeks (as they were also in our timeline, although they didn't last for long). And after giving it more thought, even if the Empire survived for a looong time (with all those regions in it), Thrace and Dacia would still be considered different provinces, which would result in a "provincial" culture for each of them (with the southern one being able to continue its relationships with the greek culture).
I'm quite fascinated about the ancient cultures, especially the extinct ones (like Thracian - and for the most part also it's subpart Dacian, as there are incredibly few elements of it still surviving today, as an effect of heavy romanisation), and I find this alternate timeline really exciting!
I think that the rightful owner of a region should be decided by who constitutes the majority population.
Hungarians can make a case for historically owning the regions, and romanians can too. It is really hard to decide who should have just judging by this.
Populations only change significantly when a region is transfered from one country to another, just like in Transylvania.
I dont't want to sound racist or nationalist, but I think tvat in today's context, Transylvania is fine where it is. I also think that regions that historically belonged to Romania but have a minority romanian population nowadays, should not be returned to Romania (ecen if not too long ago they were here) like Bugeac, sourhern Dogruja and most of northern Bucovina, and others.
I think borders should be drawn based on demographics. And I also think that in this modern day, there shouldn't be any nation left without a country of its own (that's why I think the Catalonian independence is a good idea).
After all, we should draw the borders for ourselves, not for our ancestors. It's us who have to live with it, afterall.
The Dacians (aka Getae) were just a group of Thracians. It's true, they were distinct from the other Thracians, had some customs of their own, traditions, a different religion (same Gods, but the dacians worshiped only one of them and had other religious beliefs compared to their brothers), and some other minor differences.
Most importantly: They spoke the same language! That is mentioned in historical sources, everyone in the ancient world recognised that the whole Thracian family (thracians, dacians, gaetae, other tribes - there are dozens) spoke the same language. There are some differences, it's true, especially in toponyms: Dacians prefered the word "dava" which meant "fortified settlement" and used it as a suffix in most of their settlement names, while the Thracians used "bria" (meaning city, and was used kinda like "polis" in greek), "para", "dina" and some variations of those - again those are just "preferences" and are not exclusive, sometimes they used each other's "convention" but rarely.
My point: IF the region was held by the Roman Empire, and somehow the slavs wouldn't have taken over Thrace and Moesia (like they did in our timeline, basically replacing the thracian language with bulgarian completely) then I'm pretty sure the region would spreak only one language, thraco-romanian. There's no reason why the thracian language would, after latinisation, split in two different branches considering they are part of the same realm.
If they were different realms/countries, then they would, in time, develop differences between each other, including linguistic differences. And the linguistic samples you suggested in the description are actually really good examples of how that language may diverge. Historically, the dacians were much more united, mostly under a decentralised kingdom (tribal confederation) - many suggest it was a theocracy, but evidence shows a dual rulership of the kind and the high priest holding seemingly equal power (tho we know nothing for sure). Thracians, on the other hand, were much more... "individualistic"? They often faced power struggles and different tribes fought for control of the land. They just weren't as united as the dacians. The dacians were just the same at first - they are also thracians after all - but some really ambitious men united the tribes by word and by force and put them in line. Even tho we are not sure how long this lasted, we do know that they were united also in the 1st and 2nd century AD, after which they were defeated by the romans, and the lands that were not integrated into the Empire, weren't able to gather enough power to form another (smaller) kingdom.
This would lead me to believe that in your alternate scenario, if the thracians still held their "regional" identities over the "national" ones, they would probably not be organised in one single united realm, but in many smaller ones. Which leads me to believe each of those might diverge on its own way, forming a bunch of different, although very simmilar, new languages. (Probably just like we have istro-romanian, megleno-romanian, macedo-romanian in our own world today)
Also, I'm not going to comment about Albanian. Many people think that romanian and albanian both come from the same language, but just the same, many reject this idea. Either way, even in this alternate scenario, in that region we'd still see a language that's neither thraco-romanian or daco-romanian, even if it's related or not - just the way it happened IRL.