I voted yes. But at second thought - rather no. Yugoslavia had their best run and squad IMO during the 1990 WC, eliminated only by penalties against Argentina. Events that unfolded after that infamous Dinamo Zagreb - Crvena Zvezda game in 1990 marked the end. Politically events were going on since the mid 80's of nationalism in each federation, so makes the question fictional, great one though, so congrats, Zidane82.
Croats had fantastic peak players (Boban, Prosinecki, Suker), Serbs were good as well (Savicevic, Mijatovic, Mihajlovic and Piksi Stojkovic) but they all played in similar positions and such rivalry on paper looks fantastic, but in reality creates tensions like we had last night with Cristiano Ronaldo. It's more toxic than positive. Usually teams that win WC have outstanding few individual leaders that make the difference.
Imo, Croatia has managed to slightly move away from "Balkan mentality" in the last few years with Modric and Rakitic.
Explanation: Balkan mentality is: delusion that you are the best, too much confidence, talent, but very poor work ethic.
If a Balkan Fc or midfielder plays one good game and papers hail him, he is dead and a ghost in the next 10 matches because he has bought into his own hype.
So, Balkan players often had tons of talent and good technique, but often they had poor stamina, poor workrate and they were extremely hot and cold in performances.
Another weird trait of them is: if they play as underdogs, like against Italy or Germany, they'll usually win 2:0.
But if in the next match they have to play against some minows like Cameroon or Latvia, they'll probably screw it and play 1:1.
In the next round, they'll again win 0:3 vs England.
These players and teams often played good only against good teams.
The best example of that was World cup 2002.
Croatia finished 3rd in 1998' and they had high hopes of WC in 2002'.
Before the cup, players and papers used to say: we are gonna repeat the semis.
Croatia was in a group with Mexico, Italy and Ecuador.
1. before the WC, fans agreed: it is very easy group, Croatia and Italy are going through
First match was against Mexico, fans thought: we are way better, that will be an easy game.
Mexico won 1:0.
2. after the first match, fans and media turned 180* degrees and said: we are shit, bench everyone, this is the worst team ever.
3. But then came the 2nd game vs Italy, where no one believed in that team anymore.
And of course, this is what happened:
4. after a win, players, fans and media again turned 180* degrees into: we are the best in the world mode and we'll win easily against Ecuador and qualify to a round of 16.
5. guess what? Croatia played like shit again vs a minor team and lost 0:1 again and were KO'd.
6. fans and media made another 180* turn and again moved into = this is the worst team ever, sack coach, sack all the players - mode
Basically, this is the textbook example of Balkan mentality, going from hell to heaven or from a GOAT to WOAT 4 times in 7 days.
Only in the last few years with Modric and Rakitic (and Mandzukic somewhat), Croatia shifted their mentality towards more consistency, and technique was paired with some hard work, stamina and mental strength.
Hard to tell whether Croatia will get cured from "Balkan disease" in the future.
There are some chances since we parted way with Serbia (who is leaning more towards east) and lots of players plays in Europe where the work ethic is way stronger and they are learning their way of living and thinking.
But regarding your post, I don't think that a team from 1990 was any good, because those were all CMs and CAMs with tons of technique and not much work ethic.
Robert Prosinecki, who played both for Real and Barca, was famous for world class technique, zero running and smoking cigarettes during halftime.
He was finished as a player in a late 20s, unlike Modric who is still awesome aged 37.