I'm a little late to the party here, but I'll copy/paste a comment I posted in another thread because I see it a little different than most of the arguments I've seen.
I think this was the right decision, but I'd like to make a case for something I find more important than the arguments I've seen.
It's the whole basis of our education system in Finland. From grade 1-9 there are very few subjuects that aren't obligatory. The finnish schoolsystem is not at all made to educate us for what the majority of Finns will need in the future. It's based on the idea that every person in Finland should have the equal education opportunities. This, to me, doesn't mean that all children should "get to learn the same things". It means that what ever your background is, you aren't tied to where you're from. And when you're 15 years old and have to choose which way you want to go for the first time, you still have the same possibilities as everyone else.
On the other hand all obligatory language classes could be removed from secondary educations, because that's where the individuality of finnish education begins.
This doesn't mean that the swedish education is really horrible, I understand this very well because I've stuggled with finnish alot myself. It's good they're doing the tests in eastern Finland, but I don't think it'll mount to anything because it's not doing anything about the way we learn the language. It's like saying "okay, you're not learning, so I'll change the color of the crayons." (maybe not that pointless, but just to make a point)
The way to, IMO, change the language education is to start it in 2nd grade, just not like a language. We should, except for some elementary lessons, mix it in with art, music and similar subjects you have early in school that don't require any testing at all. This could work if we remove the idea of being able to speak the full language and for the first few years you should only need to recognize and understand some parts of it. Just to take some of the pain away from learning the actual language later.
This was really quickly writen, so I probably got something wrong.
TL;DR:
Finnish basic education is based on the idea of same education for everyone.
Secondary school could skip obligatory languages.
Swedish/finnish education is horrible in Finland.
Start passive language learning in second grade.