and Maki

Emm not quite sure if I did actually understand it (is it mean "looks/appearance, right?")
I go with Umi (love her face,and facia expressions xD) ...kinda tied with Eli (even Honoka commented about her beauty) ...and I don't know, let's throw a Maki; that makes "my top 3" XP

When I hear 'character design' I think of personality, personal traits, looks and hobbies. Of them all, I picked Maki, because she was aloof at first, yet still became intrigued by the school idols and joined. She gradually grew more friendly. I like her personality - she's smart, creative and witty. I also like the character designs for Eri-chan and Kotori-chan.

["EDIT""]
Aaahh right ritght, I can't believe I haven't seen it in that way haha
Ok, so... I go with Hanayo, I smile everytime I watch her in action. She took many steps :3
Maki? that's pretty close too xD For the reasons "you" mentioned; and because I find myself looking at her in terms of music. I admire her the most :)
..And Umi. Her hobbies, activies, etc. I can't lie; I admire that

Vice President Maki! :D

I just love Hanayo look her purple eyes but if there one thing I love the most about her is her hair it is just to cute

I would go with kotori on the swimsuits but Rin obsession with ramen, her nyan, boyish hair and cuteness is a win for me

I think I like Eli's design the best, because I love the blue eyes and blonde hair on anime girls, like with Kaori in Shigatsu Wa Kimi No Uso and Chitoge from Nisekoi are good examples of these.