Most big OT9 fanbases don't care about mistreatment or whatever. Hell, they don't even support their individual activities much. Chaeyoung has the smallest fandom in TWICE so they really can't throw tantrums at every little thing like Tzuyu akgaes. It doesn't even work either.
Also one thing I don't understand about y'all is your misconception that TWICE members lack confidence. Like where did you pull that from? Girlies have no problem performing in front of thousands of people for hours straight and y'all think they have confidence issues. Chaeyoung is one of the members who has never sit out any of the performances, be it for any reason. She is the most consistent member of Twice.
And about the shipping fantasy, not to push this on the girls but Chaeyoung and Mina do mention each other a lot and at every occasion lol. Such issues are present in every popular group so that's not a problem as long as the shipping doesn't reach the girls, which it hasn't.
Well Chaeyoung is very noticeably the member who gets very nervous during Twice Encores but that's because of netizens, not anyone else. Despite being a rapper, she's Twice's 5th best vocalist: that's a huge feat for someone who is a rapper. Not to mention she's one of the most grounded Twice members (ie has one of the healthier/less-strained voices). She's the type that has a lot of potential.
I think to me, it's clear rapping is not her passion. She also to me is not a very competitive person. She looks content and happy at where she is. I don't think she wants more lines.
I think she's quite artistically passionate. However her artistic viewpoint may not be where the mainstream viewpoint lies. To me she has always reminded me of Wonder Girls Yubin (in her rapping + being a good vocalist ) + Yeeun (unique artistic direction).
Minyoung was easily the best vocalist on the show, however she struggled a lot from the transition from being a vocal student to an idol. Being an idol is quite unhealthy on the voice. You have to sing in bad condition, with a strong diet, and under a lot of pressure, especially during festivals and appearances.
Many strong vocalists flop at being idols: although their technique is good, it needs to be adaptable to many environments. It was rather common in 1st/2nd gen.
JYP realized Minyoung felt out of her element + unconfident on Sixteen, which was pretty low pressure compared to the industry. She could possibly have nervier stages at other places, and regression was almost guaranteed for her. Minyoung also got a bad edit, which sealed her lack of popularity compared to the rest. Technically was her lack of visuals related to her lack of popularity? - very likely.
JYP was technically correct in thinking Twice with Jihyo, Jeongyeon, and Nayeon would be enough in terms of stronger vocals. Twice has always been a group with good vocals, but JYP overworking them heavily took a toll on everyone's voice except for Jeongyeon, Chaeyoung and Tzuyu [who initially didn't sing much].
JYP did not plan for Twice to get this big, so he didn't expect to have them go to every festival/performance..etc. They were everywhere in 2016. JYP's producers were also pretty inconsiderate when picking songs. Factors he had not considered.