Regarding the unexpected suspicion of Joan Watson, I thought the same thing (if anything I thought the point was going to be that Sherlock was to be suspected), but then I reasoned that it’s could be explained by the fact that her encounter with Michael can be regarded as just her trusted report of what went down, not necessarily fact, and that with that view it only goes to say that she evens admits that she is tentatively the last person known to encounter (and fight and even stab/slice) him before he was found dead.
(note: I haven't yet seen the next episode)
Shout by kinkyVIP EP 6BlockedParentSpoilers2018-09-29T15:43:13Z
It was a bit predictable that Michael went after Watson, but overall this was a surprisingly good episode, proving once again that Michael breathed some fresh air into a withering show. I enjoyed very much the darker tone of the episode (again, bringing this show closer to Dexter, particularly the scene where Michael hunts down Joan in her house).
I just don't get how can Watson be a suspect of Michael's murder if she was in the hospital with broken ribs and Michael left her house still alive. Makes absolutely no sense. Maybe they'll explain that better in the season finale.