I have to post, since this is one time I agree with
Kaioshin_sama. I think the possible development in ep8 is very much like a change of tempo in a piece of music. Or like suddenly introducing a quiet passage with woodwinds in a piece that has been brass and strings. It is not unrealistic, as far as I can see, just startlingly different. That can be considered a dramatic sin or an exciting development. What I feel is exciting, moving, deep development.
My acceptance of the strange sequence of events as realistic has a lot to do with my own experience of something somewhat similar in real life, which I described
here.
And I don't know what other people watch, but this isn't a trope that's overused in my experience. And personally, I find the vagueness of the situation quite exciting. Actual literature, in fact. We ourselves are made to feel the confusion, as if we are involved in the situation.
The idea that Mirai's personal growth and this delusion are incompatible seems untrue to me. People are complex, not simple. I was more worried that her personal growth was being presented a little too bluntly, myself.
But I can't ask everyone to have the same reaction. Kaoishin's analogy feels right to me. If it doesn't to you, fair enough. It is not something that can be "proven," since it depends on one's personal aesthetic feelings.