I agree, Susi, that I think Mary got too big a role in the show. I would have preferred if her role was diminished somewhat. And I do see how Eurus is bordering on being supernatural. Then again, so is Sherlock (being able to "deduce" that Molly would be at the door at the exact moment John asks about a second opinion is nothing short of magical - and so is most of his deductions/predictions in TLD). I don't have a problem with this. I handwave it away just as I do with Sherlock having no physical or mental aftermath issues with torture in Serbia, John's issues being resolved a bit too quickly to be realistic, both Sherlock and John acting so horrible towards each other over the years that in real life I would have recommended them to run away from each other etc. It's a TV-show, not reality.
There are probably some plot holes, there always are in any show or movie, but I don't think they bother me much seeing as I can't even remember any at the top of my head. (Eurus could get out and get all the stuff she wanted because she was actually running the place. As for Sherlock not having sex, he didn't want romance/sex to come in the way of, or distract him from "cold, hard reason" and The Work).
So, yes, Mofftiss made some choices that I hadn't preferred myself, but that is to be expected. Firstly because it's their show and their vision, and secondly, the chance of their vision being the exact same as the one in my head is incredibly small.
So this leads me back to what I mentioned once on a similar thread. When I become a fan - when I fall madly in love with something - I go where they lead me. I adapt to where the show (book, movie, game etc) is going, I can't expect the show to adapt to me. So things like plot holes and stuff that isn't really that realistic becomes very minor in my head, because my love for the show overshadows what I view as minor stuff. And if the story or the development goes a different direction than I thought it would, I take a moment to regroup in my head and then I follow again, eager to see where this new path might lead me.
I want to call it loyal, but that might lead to some people thinking that if they view it differently they might be seen as disloyal. Which of course they wouldn't. I am only trying to explain how I personally see it and why I see it the way I do.