Mike,
The corruption of the Croatian Wikipedia began in 2009 and became front page news in Croatia in September 2013. The term "fake news" hadn't been invented yet, but the Croatian Education Minister issued a public warning to the country's youth in 2013 that they should avoid the Croatian Wikipedia, as much of its content was "not only misleading but also clearly falsified".
So I can't agree that this "was perceived, rightly or wrongly, as less of a problem" at the time. It's hard to imagine how it could have been more prominent.
The matter was even discussed in the US mainstream media, hardly known for detailed coverage of Croatian affairs. In October 2013 the Croatian Wikipedia's subversion was the subject of a dedicated article by Tim Sampson in the Daily Dot. In 2014 it received a mention from Caitlin Dewey in the Washington Post. (You can read all about this timeline in the English-language Wikipedia article on the Croatian Wikipedia, and the sources cited therein.)
Compared to the level of public interest eight years ago, the press had actually been quiet about this decade-long scandal in recent years – more due to topic fatigue, I think, than anything else – though there was a smattering of articles published by the Balkan Investigative Reporting Network in 2018, concluding with a report stating that the Wikimedia Foundation had refused to respond to their inquiries.[1] Ouch.
So it was all the more welcome that the WMF finally did something this year and commissioned an expert to write a report, after a decade of complaints from media and the volunteer community.
The idea to have an outside expert look at how human rights violations by political regimes are covered (or covered up ...) in various Wikipedia language versions, and summarise their observations in a public report, is an obvious one. (I suggested as much back in 2015.[2])
The costs of doing this now will hardly have been prohibitive. Commissioning a report like this would have been well within the WMF's means in 2013 as well. (The WMF reported a budget surplus of $13 million in 2013.) So I stand by my assertion: the WMF could have done then what it has done now, but lacked the will, or courage.
You are right about one thing – in matters like this, both action and inaction can be construed as a moral failing. I absolutely applaud the decision made in this case, but can also imagine that, the precedent having been set, scenarios might arise some years down the line, under different leadership, where the same type of WMF action could be more problematic. This is something for the community to watch out for.
Andreas