you know... I started to read this since it started but dropped soon after getting tired of the balless MC, but as the masochistic person I am (I have a hard time actually dropping a series without knowing how it end and most of all curiosity while bored), I continued to read the series from time to time... and goddammit I don't regret my choices in calling him balless a long time ago.
doing a read since ch. 1 and he has some inner thought that reflects maturity but when we go to actions he hasn't grow at all (maybe with Sumi as she is even shyier but even her grow a huge amount between her first and last appeareance).
the one actually growing as a character is Chizuru. Ruka is still acting as a kid (and she is, problem id by how long they have kept their shit, she should accept if Kazuya breaks up with her, also she's still talkimg about the time he almost wanted to go official and it went for months since that event, did the author forgot that??)
well that's my rant, author wanted to milk the series and succeed at it, 'cause it actually got an anime adaptation.