I have not watched the BBC documentary, so commenting on the specifics of it would be rather dis-honest, though I have heard that it is great at what it does, as long as we know what it is doing. We should net be surprised about this particular narrative technique to be used by either popular-minded history books or documentaries, as this is the most "engaging" and single-oriented approach for basically any period or event in question. So, as long as we are conscious of these facts, there is little to be said. We do not expect to find a broadness ( in this case of documentary, we get the picture of "broadness" from multiple parties in conflict ), nuances, conflicting and aligning factors, cultural and social aspects, economical factors, and legions of others, yes, even the leading personalities. But the caveat being that if I peruse the library for academical theses now, I will find, for example, The Degree of Influence by various political personalities on the Independence of Slovenia by B. Jus, which analyzed not only Slovene, but Croatian and Serbian figures as well, which tries to critically evaluate a complex situation and interdependence of factors.

Historiographically, it is only one ( though it is a matter of contention about how ) of the important factors one has to critically implement, and singular popular "great-man" can be an object of study by itself as a historiographical method, but hardly anyone uses it as an actual method, without explicitly stating so or having that as an actual object of study.

I cannot comment whether they had Kaplan specifically in mind with the making of the documentary ( Kaplan has not been received well in academical history generally. ), though one can number numberless reasons why such a narrative from a few leading personalities was used.

Sure, to enumerate some of them, -- although I cannot say whether there are good post on the topic already existent, you can make a post ( and ping it on me ) and I can go over these singularly in much more detail -- namely, economical crisis starting in late 70s into 80s, and utter failure to address it, specially under Duranovic-era, while there were influential works coming from non-government related individuals / institutions, that were critical of its handling, like Jugoslavensko društvo u krizi by B. Horvat, Kosovo unrests, perhaps not by itself, but with a more broadly sympathetic sentiments to violent suppression of Poland protests in 82, and the parallels that emerged from this, widespread censure, JLA, persecutions, differences between the republics ( in factors enumerated ), literary revival and bringing into light post-war killing, Dachau trials, not necessarily as events in themselves, but in a more broad political significance, we get highly impactful works on politology like Stranacki pluralizam ili monizam : obnova i zatiranje posleratne opozicije by Kostunica, we have new publications which sought independence from political overview, like Slovene Nova Revija. As said, I would gladly expand on these specifics if requested.

Meanwhile, I have found this article that might be of use for the Kaplan thesis in question.