[Klashikari]

I personally think the conclusion had a proper touch regarding Rikka's case: certainly, it isn't like you had a clear cut answer to her antics but what Yuuta actually did was "using" Rikka's chuunibyou in order to make her settle down her regrets. Surely, this episode did explain why Rikka "suddenly" shifted into chuunibyou, but how she used it was initially for fun until it became basically a reality substitution (portrayed by how her house was conceptualized in her chuuni mode back in ep8).
And since even her own anchor and "admiration source" told her to cut off with chuunibyou, only her bottled emotions regarding her father remained (due to her "duty" to follow society rules), obviously left with basically nothing.
However, now that Yuuta lead her the way to actually use her chuunibyou (however how "effortless" it was, save the actual epiphany from Yuuta), she could finally drop the initial catalyst of her chuunibyou, with only the fun stuff remaining.

So really, whereas I can surely agree that some things are missing regarding Rikka's family (some circumstances, such as her mother and grandparents), it surely dealt with the core of the drama regarding Rikka's part. In a sense, that definitely works as a "proper ending" in my books. That being said, I share the sentiment they should have done a 2 cour series with more spread stuff regarding the drama, so we don't have a "mood swing/genre shift" impression.


A side note: I see some people mention "Deus Ex Machina" regarding the club members intervention despite there wasn't any (at most, convenient, I will give you that).
I mean, even if Makoto was a sidekick, he was pretty much part of the club, so what stopped him to contact Kumin, Sanae and Shinka? Actually that do make sense they could reach Yuuta and Rikka on time considering the circumstances:
1) Sanae has her personal chauffeur (sort of hinted beforehand by the ojou stuff)
2) They actually know where Rikka's grandparents live due to summer vacations
3) Makoto figured out Yuuta's actions are hardly for the kicks.

The only questionable part is Kumin's location, but if we assume she livse nearby, she probably knew where Yuuta would pass by bicycle. Still a bit sketchy indeed, but not out of thin air/ass pull than what a true DEM is.