This article really makes sense about what is good about Croatian football.
It claims they play a lot of street football - unlike many other countries in Europe. In 2008 when I did a Dutch KNVB Advanced Coaching course under the tutelage of Arie Schans and Ad Derkson, they constantly alluded to the problem that less and less football was played by the current techno zombie generation.
There was also a claim Croatian kids spend more time outside, playing a lot of street football. Croatian TD, and in a different era Dinamo Zagreb TD, Romeo Jozeak also suggests that a lot of street football means players have to unlearn bad habits.
Other countries of the same size, Denmark and Scotland, aren't producing technicians the same quality as Croatia.
Croatia also has a national , holistic programme. Facets of technique in football, like being two footed, developing ball mastery, plus having athleticism, are supposedly emphasised by professional coaches across the country. Ostensibly they access children at a young ages of 7-9 to acquire good habits in academies throughout Croatia.
These aspects of the Croatian football milieu are more likely to be producing quality players than nationalistic arguments about sheer innate talent being a factor.