Hahaha. I dunno. I think the idol world has gotten big enough that people like Haruna and Tomo would have been successful, had that wanted to. They could have turned their actual strong personalities into their idol persona.
I mean, look at people like Sashihara Rino. She's very much her own person, very outspoken and opinionated. It wouldn't surprise me at all if, behind the scenes, she gave producers or managers an earful if she were asked to do something she didn't want to. Haruna probably would have been along these lines, and could have made her "icy glance" her signature expression. That type of thing could have been successful on shows like AKBingo, just like Myao's being mean or Akimoto Sayaka being kind of scary. Same idea with Tomomi; her quirky character would have been a hit among idol fans, I believe. Even now, as non-idols, she's hilarious on variety shows.
In any event, we'll never know. I just think that all of them could have been successful as idols, had they so chosen. All four are definitely attractive enough. They are all good enough as vocalists. We know they all had dance experience, considering how they met. They definitely have the work ethic.
I'm glad they didn't go the idol route, though. Scandal is definitely a group where the whole is greater than the sum of it's parts. They each seem to make the others even better in a sort of awesome positive feedback loop.
On Topic: Demonstrating my lack of knowledge here... Who is the YUKI mentioned in the blog post? There are lots of Yukis in the entertainment world, so YUKI most be someone specific?