Courtney had relatable problems compared to Marland's main pretty princesses (Lily, Rosanna), and I think there is something to be said with her struggling with her body image, with Andy's inability to break out of toxic patterns, etc.
The main reason I don't care for her is because onscreen, I just don't think this was very interesting to watch. She spent years being unhappy, with little to no personality trait beyond being unhappy. Whether she was with her brother, or Ellen, or Andy, or Evan, that was all you got. She had no real personality or inner life. That's why when she married Andy, her story was essentially over, and we got odd writing choices like her becoming a cop, which I never remember her caring about before that point.
Andy was one of my favorite characters, but I generally was more drawn into his stories when they had some type of ugly dramatic element, whether it be the consequences of his drinking, or his relationships with "bad girls." I'm not saying Courtney had to be "bad" to be interesting (Iva, Connor, etc. weren't), I'm just saying the Courtney we got, in writing and acting, felt like a drag to me. As time passes I blame that more on Marland's problem writing for ingenues, and less on Hayley Barr, who went on to do some good temp work on GL (to the point where a number of fans who were tired of Beth Ehlers wanted her to take over the part).