Why don't you think Ron and Hermione aren't a good fit? Do you feel the same about Harry and Ginny?
I love Ron, but I don’t like the way Ron treats Hermione, and I don’t think that fight all the time means love. In my opinion, a relationship like this is not healthy.
Now, about Harry and Ginny… I think Ginny loves the hero,not the boy…she’s just a fangirl. And I just can’t understand the way Harry started to love Ginny… he spent more than 5 years without even notice her. They barely interacted until the 6º book, and then, it was like he woke up and decided that Ginny was always the love of his life… it doesn’t make sense!!
I think JKR didn’t even tried to build this relationship… it was just like “shit! it’s the 6º book… it’s almost over and I forgot to put Harry and Ginny together as I planned before I start the 1º book… here, I’ll put a chest monster that comes from nowhere, I’ll call it love, and it’s done. They’re soulmates.”