Watched it at the weekend.... Wow, was not expecting that! Overall, despite a few annoying things, I loved it and it is a TV show that I have been thinking about since I finished which hadn't happened for a while!
It was annoying when the genre switched - when they started doing to above shots with the coloured light overlay I was thinking, 'so she is psychic?' and thought it might be to do with the drugs, but then realised it was taking a supernatural turn. I agree that generally, viewers/readers want to know what is plausible in the universe they are immersed in, so it was kind of frustrating when that revelation happened.
Still don't really get why Louise projected to get into the burning house, was she going to try and go into Adele and make her get up (did she even know that was possible at that point?). Why couldn't 'Adele/Louise' move when they swapped, same as when 'Rob/Adele' was paralysed when they swapped in the woods? Was it because of heroin, or was it because Rob was first to go back into the other body both times?
Also, when David went back up to Scotland to sort stuff out, what did he tell the police? Wasn't there an investigation into Rob's death, why David's watch was down there with him? David was mostly a dick throughout and I didn't really get what Louise saw in him (apart from him being so easy on the eye and a good shag!).
I also thought they should have dropped a few more hints about Rob being capable of something so terrible. He came across as very sweet and just sort of harmlessly jealous not the total psycho that was living in Adele. The only hint was the sister saying he was a nasty piece of work.
Also, didn't get the significance of the pills in Louise's early dreams, as she hadn't even met Adele by then? There were a lot of coincidences (eg. Louise happened to have night terrors etc) but I think that it was just that Rob/Adele saw the ideal opportunity to move on and took it, Louise was the perfect victim.
So sad for both Adam and Adele, who was lovely all along! I'm so tempted to watch it again and look for clues!