I like her, she has a sexy body, nice butt/boobs, a pretty face, charming personnality on camera.
Actually Yua has a better face for j-pop than other things. What I mean is, her face is really so so, when the camera do a close up, e.g. in the youtube vid you posted. And for JAV, Yua's face is nowhere near top 5, by either my standard or some kind of community standard. Her face reminds me of Ayaka Tomoda, looks like a MILF rather than young hottie. For j-pop it's fine, especially in a group. The camera is mostly zoomed out to watch the group and/or the dance moves. Her face has a good general shape and big (un-Japanese) eyes, so with skillful make-up her face is perfect for j-pop group.
Her tits are nice, but nothing special in 2017. It seems nowadays 3 out of 4 debutantes have amazing awesome big tits. Yua's are... meh... just nice.
Rest of her figures are also very nice, but again not that outstanding in 2017.
And now we have really quite enough data points, J-pop (AKB or others) or other celeb credentials are good for 1, at the most 2 (TWO) free passes. I.e. guaranteed good sales for a vid. After 2 releases, more than half of the celeb-turn-AV-sensation disappeared and forgotten. Only a few sustained 6 months, and only very few achieved anything close to a career in AV.
So I'd argue Shoko and Yua's mere survival (not to mention excellent sales) is much much more than banking on ex-celeb status.
In Yua's case, let's be fair, her sucess is totally disproportional to her physical assets, face and figure. There are so many younger, hotter and bustier competitors.
Yua is very smart on self-promotion. Her weapons are pure and simple: image-engineering and fan-service. she's great at pretending to be an idol, despite, obviously her J-pop talent is mediocre. And she works very hard giving what fans want on the vids and off-the-vids, great fan interactions.
She won the DMM award by doing what other candidates can't or won't do: self-promotion and mobilizing votes (you can say stuffing the ballot box). The award was almost tailor-made for her. The vid that darksider59 posted is a textbook case of self-promotion. Someone like me find the vid itself to be very boring, except I forced myself to watch it because I want to know more about her and what tickles the AV fandom. As I understand it, it's a simulated date. An otaku fan boy watch this interminable vid instead of going out and ask a real girl for real date. (yeah I'm ready to break into fan-loathing mode again) Yua did a great job making this vid for them. It's the kind of things many AV idols lack the "talent" or energy to do. ESPECIALLY RION.
Even through it's a highly produced PR vid, there's a lot of Yua's personality (or persona??? it may be very blurred distinction for Yua) At 7:00 mark of that video, a leisurely paddle boat (which almost always means the BF, in this case the fantasizing-fan being played by the behind-the-camera-cameraman, doing 200% of the paddling while the GF enjoys the scenery and complain the sun is too much) turned into a high speed chase just because a boat nearby had a crazy couple in it paddling rather hard. The competitive instinct in Yua fired up, completely irrational, there's no point to the race, the other boat didn't challenge or dis or even notice Yua's boat. But Yua made it a race, a race that the other boat didn't even know about, and she paddled much harder than most typical GF. Of course she lost, but that irrational-can't-lose-even-if-it's-not-a-race beast is in her. She's like a little dog that can't stop chasing the fire truck, that moves me.
Then if you go over the whole 17 minutes of it, there's a lot of want-to-win moments in this otherwise highly otaku vid. There's the spirited run up a long steep slope (I dare say 90% of her fans can't match her speed and stamina) the downing of a very hot spicy lunch, the baseball pitching game, the hand-eye coordination game, the karaoke game. She aren't great or very good at some of these things, bur she seeks challenges and give more effort than most AV idols and AV fans.
So yeah, on one hand, a simulated dating vid is still boring as hell. But put all these moments together, I get the picture Yua may lack any serious talent (to make it big in AKB or J-pop) and top class beauty. But she's very competitive and wants to win, even when the winning is totally pointless and irrational (e.g. the hot curry, the paddle boat race). So fucking yeah, I get a huge erection for this chick.
Remember when she started with Muteki and even after transferring to S1, I was hugely skeptical of this girl. Seems she was a naughty trouble-maker, an untalented failure and a cheater. She looked like she was a short-sighted, prima dona wannabe, but lacking the discipline and talent and beauty to get what she wanted. I was waiting for her to crash and burn and ended up a tragic story.
But her steady release of high quality S1 vids, despite being rather conservative and boring as S1 always is. She changed my heart and mind. She works hard, she wants to win. True a lot of things she does is to cater to the kind of fans I loath, but while I don't enjoy a lot of things she does, I totally respect she makes herself a winner. As far as I can remember, she's the first celeb-to-AV superstar, she did and continue to do what I wish someone would do but seemed never to happen: she made a perfect unbroken bridge between celeb and AV. She didn't just cut off her celeb past become a success in AV, that would be impressive but not enough for me. She maintains and actually grew her celebrity while being in AV. To me, she is (or will be) the Bob Dylan of AV.
Even a crazy idea come to me now, thinking back to her trouble days in AKB, perhaps it wasn't a matter of her being troublesome but the problem is that AKB isn't a good place for individuality seeking success.