I absolutely loved "Flatline". Jamie Mathieson is welcome back any time. A great concept, very well executed. The Boneless when they finally appear properly, are quite creepy. They are getting very adept at making (and masking) these Doctor-lite and Companion-lite stories as they did in this story and the previous one. Other than Capaldi's changing hair cut, it's all pulled off perfectly.
And then there's "In the Forest of the Night". This is definitely my least favorite story of season 8 and one of my least favorite stories of "new Who". While it's not dull and unwatchable like say "Fear Her", it just felt so stupid and poorly conceived. Where are all the people?! Isn't London a giant city with millions of people living in it? Where are they?! And even if I believe the trees can grow overnight and then magically disappear in fairy dust the next day (which I don't), you mean the buildings, streets, and landscape are perfectly unscathed afterwards? Really? And how exactly does the missing sister magically reappear with the disappearance of the trees (and apparently one bush)? So, this story featured a natural event that seems to threaten the Earth where the Doctor figures out the proper course is to do nothing. Didn't I already watch this in "Kill the Moon"? Oh, and I didn't like that one much either. Let's do it again a few episodes later.
I am however, giddy with excitement for the two part finale. That trailer looked fantastic.