I'm not sure that's bad, but this article seems to neglect to mention that nothing comes for free. This isn't just "doing it smarter", it's also investing a massive chunk of money.
Additionally, I honestly doubt it's sustainable. The example of the Kosovar kid with a language delay is telling: this will only work if there's only a few such kids in the school at once. With immigration to Finland strongly increasing over the past 5 years, the problem may at some point be more difficult to tackle the "traditional way" when, at least in certain cities and suburbs, half the classroom has trouble with the language. I don't think there's an easy solution to this.