Hmm so my Big sister is rather short novel is something surprising to me since how each part is written I was thinking that it was planned to have at least dozen volumes, as for other novels i read means Paying to win it doesn't surprise me at all since i do not feel like it could have much more material to write.
As for Mixed Bathing I'm surprise that WN didn't was longer before getting published.
I believe the first series to be completed by J-novel (besides one volume long brave chronicle) will either bluesteel Blasphemer or My Little sister can read kanji. I also feel it would be great idea to celebrate it on j-novel by either announce new license or maybe something else (like some promotional action).