Nobody is denying that the Russians preferred Trump over Killary, not least because of his campaign promises about trying to fix the relationship that had so much suffered due to the machinations of mostly Obama's State Department and CIA.
As to the "Collusion" conspiracy theory, at the forefront of research is now who did what in the small group which hoaxed that CT. The FBI side is pretty clear, the DoJ side 
is under increasing open source investigation at the moment.
As a main goal of the hoax dossier was to get a warrant to spy on the political opponent, which was successful and led to the gotcha! moments with Flynn and Papadopoulus, it is totally clear that no surprise revelations are to come from the Mueller investigation. Because if there were a there there, we would know for a long time already, thanks to the surveillance. 
The revelations to expect are in the investigation of the conspirators to hoax a conspiracy. 
Results due in January.