This is the cinematic version of a "F*ck you"
The movie is a big, pretty piece of f*cking nothing. Nothing happens in the grand scheme of the Chuunibyou series. There are no themes here that aren't tackled somewhere else in this series, but the worst part of it is it dangles genuine character growth in front of you and then it spits on it and sneers at you, "How could you? How could you genuinely expect these characters to develop and change and grow? Don't you know you need to accept all the imperfections and bla bla bla"
Rikka's character arc in this movie is utterly ruined, because it would rather pander to it's base and keep everyone's precious status quo than possibly challenge the viewer. These characters are stuck undergoing their Sisyphean task of being the same dull characters they were in the rest of the series.
The idea of Rikka finally maturing and dealing with the adult world in a healthy way is a very interesting one, but the execution is atrocious instead choosing to romanticize her unhealthy delusions because "As long as someone encourages you delusions- I mean loves you for you are, you need not grow" She has grown past the need for these eight-grade delusions, but because the audience hasn't, she will be perpetually stuck as a mentally ill teenager.