Historically Moldavia was dominated from the year 900 by different Turkic tribes Pechengs, Ouzes and Cumans, only around 1150 do the Principality of Halychs and the Kingdom of Hungary compete for the control of Moldavia, but by the 1200's the Mongol Horde came and the Principality of Halych had been conquered. Thats like 50 years of barely any control on Moldavia by the principality of Halych, as you can see on the map during its greatest extent it controlled barely the northern region of Moldavia and Basarabia and as you can see from the other maps, Pechengs and Cumans held more teritory and longer than Halych had.
And this map showing the extent of the Cuman Khanate before the Mongol Invasions. No need to discuss the mongol invasions as Halych couldn't possibly hold Moldavia during that period for obivious reasons.
Domination of a land inhabited by East Slavs which was contested by Kievan Rus'.
867 (CK3's earlier start date)-940: "The Uliches or Ugliches (Russian: У́личи or Угличи, Ukrainian: Уличі or Угличі) were
a tribe of Early East Slavs who, between the eighth and the tenth centuries, inhabited (along with the Tivertsi) Bessarabia, and the territories along the Lower Dnieper, Bug River and the Black Sea littoral. [...] The Uliches long
struggled against the Kievan princes Oleg, Igor and Sviatoslav Igorevich for their independence, until a Kievan commander Sveneld captured their capital, Peresechen (near Orhei, in present-day Moldova),
around 940."
en.wikipedia.org
And then we have the period from the 9th to the early 11th century:
"In the 9th century the Pechenegs began a period of wars against
Kievan Rus'. For more than two centuries they had launched raids into the lands of Rus', which sometimes escalated into full-scale wars [...]
The fortunes of the Rus'-Pecheneg confrontation swung during the reign of Vladimir I of Kiev (990–995), who founded the town of
Pereyaslav upon the site of his victory over the Pechenegs,
[39] f
ollowed by the defeat of the Pechenegs during the reign of Yaroslav I the Wise in 1036. Shortly thereafter, other nomadic peoples replaced the weakened Pechenegs in the
Pontic steppe:
the Cumans and the
Torks. According to
Mykhailo Hrushevsky (
History of Ukraine-Ruthenia),
after its defeat near Kiev the Pecheneg Horde moved towards the Danube, crossed the river, and disappeared out of the Pontic steppes."
en.wikipedia.org
Followed by the aforementioned Principality of Halych expanding either directly or through soft power in Northern Moldavia during the 12th century, while in the south:
en.wikipedia.org
"The Cumans initially managed to defeat the Great Prince
Vladimir Monomakh of Kievan Rus' in 1093 at the
Battle of the Stugna River, but they were defeated later by
the combined forces of Rus principalities led by Monomakh and were forced out of the Rus' borders to the Caucasus. In these battles some Pecheneg and Oghuz groups were liberated from the Cumans and incorporated into the Rus' border-guard system."
And in the 13th century:
en.wikipedia.org
"
Roman turned his attention to the Cumans, who were threatening Byzantine interests in the Balkan Peninsula, and
agreed to come to the assistance of Emperor Alexios III Angelos (1195–1203) and a severe blow was administered to the nomads. [...] The relation with Byzantium helped to stabilize
Galicia's relations with the Russian population of the Lower Dniester and the Lower Danube."
As for the Mongol invasion, the aforementioned Roman's son:
en.wikipedia.org
"Yet Daniel's successes and his failed defense of Kiev attracted the further attention of the Mongols. In 1246, he was summoned to the capital of the
Golden Horde at
Sarai on the
Volga River and
was forced to accept Mongol overlordship. [...]
By his death in 1264, Daniel had reconstructed and expanded the territories held by his father, held off the expansionist threats of Poland and Hungary, minimized Mongol influence on Western Ukraine"
It also makes sense from a gameplay point of view as i believe Wallachia and Moldavia should be in the same empire (would be wierd if separated), otherwise playing as the kingdom of Moldavia would encourage you to rather create the Russian Empire instead of conquering Wallachia and Hungary, countries with whitch it had much more interaction throughout the period.
Only in the late game's timeframe when the historical Moldavia was formed. But otherwise, the CK3 startdates will incentivize preexisting Kings and (future) Emperors to conquer the lands of de jure Moldavia and form it, so it's not a matter of where the AI would expand as King of Moldavia, but rather who will expand into de jure Moldavia - Kazharia, Russia or Carpathia.
Renaming Carpathia to Hungary makes no sense, there are not only Hungarians in that region, imagine Pechenegs, Vlach, Slovien, Avars, Bulgarians forming the Hungarian Empire.
Agreed, though it should ultimately be defined culturally as is the case with the Britannia Empire (i.e. Empire of Carpathia being called Empire of Hungary when held by a character of Hungarian culture).