I might as well chime in with the stuff peeps have already been saying
Haruna is a cute girl, and has potential, but to me her best right now doesn't come close to Kaori. Kaori's biggest problem is she's awkward as hell and can't take a picture or work the camera to save her life. Those factors honestly make her look worse than she really does. The closest comparison in current H!P to what I mean is Captain, who takes derp pics but blows the doors off of every other Berryz in person. At least in her case she can work the shit out of a dance where Kaori can fall down at any given moment. Long story short, Kaori would look hotter making a sandwich then she would posing for a pic in an elegant dress. She's best at rest.
Also though, Kaori's personality is really a niche thing. I TOTALLY get how people wouldn't like it. Hell, I thought it was awesome at first which is why she was once my favorite but as I got older, I didn't like it as much. I look at her in that regard kinda the same way as I do Yurina. They don't carry themselves as attractively as they physically are. Yurina's still a kid though where Kaori just didn't have it in her. Anyway though, Haruna's looks remind me of the 16, 17 year old Kaori. Difference is though Haruna can actually smile for a camera right.