Yes, Croatia moved to OIB, which is randomly generated unlike the MBG which was derived and contains personal information, like date of birth, region and gender.
Both points sound really weak I‘m afraid. From the perspective of a ruler of a country, both are much larger attack vectors for adversaries than opportunities for myself.
> Countries don’t really want unique IDs per person
Given the number is countries that already have those and those that attempt it every few years... I'd say it's not correct.
For spies, you just issue multiple identities - the origin country shouldn't have any issues with that part. It already happened for witness protection level stuff.
For voting... yeah, that's a citation needed. Politicians mostly worry about foreigners coming to vote.
https://en.wikipedia.org/wiki/Personal_identification_number...
which superseded the JMBG
https://en.wikipedia.org/wiki/Unique_Master_Citizen_Number