Nah, I love your post, you made your points very clear. Personally, I don't bother very much myself with oricon. When I want to find sth new I browse forums, ask people for suggestions. Like I bumped into the "Callme" trio. Totally not trendy but I enjoyed it. Jpop is a huge scene. Obviously I would prefer if there were less idol groups and more artists, that are really into their work, on top but oh well... what can I do :)

So, I got into J-Pop in 2012 because of K-Pop. I've been a fan of K-Pop since 2010 and I decided to check out J-Pop too, considering many korean artists such as BoA and TVXQ! have japanese releases.
The first japanese artist I've heard was Ayumi and shortly afterwards my very first J-Pop obsession was with the infamous quartet of Ayu, Namie, Kumi and Hikki.
To this date, Ayumi still holds the number 1 as my favourite artist of all the time. I have a endless list of favourite J-Pop artists, but I can say that so far this year, my main obsessions were with Namie, Ayu's remixes and even though it's not quite J-Pop but it's sold just in Japan, I've been obsessed with eurobeat. I also started to listen to 70s/80s J-Pop artists such as Akina Nakamori, Matsuda Seiko, Yamaguchi Momoe, Mariya Takeuchi, Wink and Kudo Shizuka.