Whilst this is ongoing, there would be risk of US extradition requests were he to leave the embassy (to Sweden or elsewhere). His best strategy is therefore to stay in the embassy for now.
Of course his best strategy is to avoid prosecution. That should mean we condemn him as a hypocrite, instead he has actual supporters blaming the victims!
The initial prosecutor dropped the charges, but another prosecutor with a political background and a radical stance on what should be considered rape appealed that decision and got herself appointed to the case. She then declined multiple requests to schedule another interview with Assange (both in-person and via phone/video conference, which Swedish law allows).
I don't understand how anyone could claim, with the facts we now know, that this case has any merit at all and is more than a politically motivated smear campaign.
So the Swedish courts certainly don't agree that this is a case without merit.
I'm usually the last person to fall for any kind of conspiracy theory, but this case could literally be taken straight from one of Kafka's books. Given all the things we know about this case, and things that went on during the peak of Snowden's story (presidential planes forced to land, among others), it would be naive to think this is not politically orchestrated, and arguing on technicalities plays right into their hands.
Prior to that they were dealing with an obstructive, bail jumping individual thumbing their nose at the legal systems of two countries (the UK and Sweden). Assange appealed extradition all the way to the UK Supreme Court then decided he didn't like the outcome, quite why the responsibility is on Sweden to cave to his demands has yet to be explained.