My Swedish friends say...
...it's a complete stitch-up.
All this information and more has been in the public domain in Sweden for quite a while. The overwhelming majority of the population appear to be surprised at the action of their authorities in this case - they find it all highly unusual. And most think that that the case, is an excuse the get Assange detained somewhere, prior to an extradition to the US.
As a country, Sweden isn't usually one to kow-tow to American whims, but nor are they usually pitched against the US either - so I tend to take these opinions at face value.