If they could come together as one they would have had a very decent shot in several tournaments
1992 - Yugoslavia won their qualifying group. Because of the war the team was disqualified. Thus Denmark took their place in the tournament and won the whole thing.
1998 - Croatia got bronze. Add Mijatovic, Mihajlovic, Savicevic, Jugovic, Stojkovic, Milosovic, Kovacevic, Stankovic and that team has enough to beat both Brazil and France.
2018 - Croatia got silver. Add Matic, Milinkovic-Savic, Kolarov, Tadic, Mitrovic, Ivanovic and that team at least gets closer to France.
And that's mostly Serbia and perhaps some Montenegro in there (played together for a while before splitting around 200*s).
Also imagine adding some of these guys to the team Pandev (Macedonia), Dzeko, Misimovic, Ibisevic, Salihovic, Begovic (Bosnia), Jovetic, Vucinic, Savic (Montenegro), Zahovic, Ilicic (Slovenia), Cana (Albania).
For those who are unfamiliar with exYU, it would be nice first to Google, after that you can give your opinion. And for the last 20 years as you speak..they would feck England 24/7, like Croatia did wonderfully. Funny people
Yugoslavia as a united country would probably fecked Croatian success. I say that as a Serb. Back in Yugoslavian days you had to play few players that absolutely did not deserve to be there to satisfy cravings of each republic. It was not a problem in other sports but in football for sure was. You had to put a Bosnian/Macedonian/Slovenian somewhere in the line up and balance of Croats and Serbs had to be right.
Part of the problem in the last 10-15 years would be that a lot of their best players were in the same positions. For example, there a while ago, they had Pjanic, Matic, Modric, Rakitic, Brozovic and others to play midfield, all looking to play in a similar way, but you can only play 3-4 of them max, meanwhile their wingers at the time apart from Perisic were not much to be writing home about.