>>103661655
It's not that deep, Koyori is just not very charismatic. She doesn't have the same sense of humor, cuteness or natural entertainment value as the bigger girls. She tries to make up for that with her non stop high energy and it works well enough but it always comes off as a bit forced and stilted. At the end of the day it doesn't really matter, she is still very successful due to her incredible work ethic and smart content choices. A perfect example of hard work making up for a lack of natural talent.