If its Russian, why would they care other than an effort actually didn't work. In the grand scheme of things Russia isn't going to be overly worried about Sweden. So I figure at most, they will have to figure out some new tactics to avoid detection and keep doing it till they get it right, if ever
Those are the conventional military-strategic concerns that are supposedly making Russia so nervous about NATO aggression. Crimea is (allegedly) important for Russia's naval security, so had to go back to Russian control. Actively driving a geographically strategic country, with resources into increasing it's naval power and seeking an alliance is losing at strategy.
On the economic, Oil prices have recently dropped. They may drop further. Russia is very reliant on oil revenues for public funding. Europe and the US are nearing the point of sanctions. Foreign investment is taking a hit. New energy projects like gas pipelines are unlikely. They do not need some pointless costly conflict.
IMO, it comes down to this. An direct NATO-Russia conflict is unlikely. The cost is too high for all parties. But tensions can rise and relations can deteriorate. Russia seems to think that's ok, borderline desirable.
They are. The article even states the reason:
The Nordic country has also drawn closer to NATO in the past few years although the current government has ruled out seeking membership of the U.S.-led alliance.
Also, it would not be the first time (http://en.wikipedia.org/wiki/Soviet_submarine_S-363). Of course, that happened in the past era, but the recent events have shown, that history tends to repeat itself.