Good job with this review, as usual I have prepared some questions:
1-Are there gonna be events regarding the rise and fall of the Serbian Empire?
2-What's the 3 Venetian colonies' primary culture, Venetian or Greek?
3-Considering how many catholic tags are still present in 1337 is there something to rapresent the "will" of the crusader states to restore the Latin Empire(and maybe the kingdom of Thessalonica) like a situation or an IO? After all there was still a titular empress with a claim to the throne(Catherine II of Valois-Courtenay).
4-Does the Byzantine empire start with the embraced meritocracy institution since historically they had a very beaurocratic administration similar to the Chinese?
5-Is bulgaria considered a Kingdom or an empire tier tag at the start since the country is know to this day as the second Bulgarian Empire and their ruler is a Tsar which comes from the word Caesar and was used to refer as someone on the same level of a Roman Emperor?
6-Do Orthodox tags need to "have" an autunomous patriarch to elevate themselves to the rank of Empire? If not then it should probably be so since that's basically what Serbian, Bulgarian and Russian rulers did to gain the authority to become Tsars and it also has to do with both Catholic and Orthidox theologies, which say that the only Christian empire in the world should be Rome(Hre for catholics and Byzanthium for Orthodox under the Ecumeniacal patriarchate), both the Bulgarians and Serbs had to break away from Constantinople and Byzanthium to declare themselves emperors while Moscow declared itself third Rome after the fall in 1453
7-Does the count of Salona Alfonso Fradique start with ownership of the location of Malta? He was count of Malta in 1337 which unlike Salona(which was under direct vassalage of Athens) made him a direct vassal of the King of Sicily, so it would be more accurate to have Malta as a tag from the start in a P.U. with Salona especially considering he's an illegitimate son of the King making the situation quite interesting.
One last thing could you post the current flags of the tags in this region please? I was thinking of making a thread about the most appropriate ones for the time period since I doubt there's going to be a "tinto flags" any time soon!