I think Hyewon is like a smaller forehead version of Hara. It was a clever way to promote her even before Co-Ed's debut, going on and on about her looking like Hara.
She looks pretty much the same in my opinion. Makeup does wonders so I think she could easily be one of the few idols that haven't had anything done for their faces.
She should get more lines. I like her voice a lot. She may not be the best singer, but I still think there's just something about her voice. It's soft and cute. She just needs to learn to control it a bit better.