I do not like the way the romances were handled.
It has always been my opinion that the two main teen pairings were very poorly handled, and that both couples have fundamental problems in their relationships. I don't have a problem with Bill/Fleur or Remus/Tonks; I think that those adult pairings were realistic and developed the characters in question very well (particularly Fleur, whose nurturing side we got to see, and Remus, who finally worked through his self-loathing and realized that there was more to him than just the wolf). I just don't think that Rowling did the teenagers justice at all and wish that she had just kept them all as friends. One does not have to marry someone they met at age 11. Most people don't.
First, Ron and Hermione. I say this not as a disgruntled Harry/Hermione shipper—I am not and never was—but I don't have a lot of use for Hermione for giving Ron Weasley the free pass that she did. He was a complete jerk to her throughout years 3 and 4, as well as year 6. In year 7 he decided to be "nice" to her, but it seems that he only did this because his dating how-to book advised it. Even though he complimented her throughout the year, I don't regard emotional manipulation like that to be actual respect. And I'm not too impressed with Hermione not ever calling Ron out on his little act and demanding true respect from him. It just demonstrated that she was so emotionally needy, so desperate for him, that she didn't see or didn't care what he was doing.
Ron, for all his "good nature," does not respect women. He thinks he has the right to direct Ginny's love life, he uses Lavender Brown to make Hermione mad at him, and when that doesn't work, he sweet-talks her into going with him. My suspicion is that Ron grew up in a household with the twins as his role models and his mother as a continual bad example of what a "woman" is like. Molly Weasley is a formidable figure, but as a parent, she is far from ideal, and she was the female role model in that household. The twins' behavior leading up to the Yule Ball is despicable, and they are most certainly responsible for Ron's mindset that led to his remark "a pair of trolls." Ron had to trick and manipulate Hermione with sweet talk once his other plans failed, from a book called "12 Fail-Safe Ways to Charm (read: manipulate) Witches." Now, I understand that it's sometimes necessary to sweet-talk people, but a romantic relationship should be the exception to that, and should be built on openness. Even in the Epilogue, Ron is shown lying to her about Confunding the driving examiner. A relationship built on deceit is not cute and it's not romantic.
However, the fault does not lie entirely with Ron. Hermione is an extremely domineering, bossy personality who thinks that she always knows best, and does not hesitate to say so. If Ron does not respect Hermione and has to lie to her, it may very well be out of fear. He may feel that his only chance to have some peace is to be deceptive with her. I never got the feeling that Hermione truly respected Ron's own choices, or, for that matter, too many other people's either. She always felt that she had the best answer and had a real problem leaving people alone if they differed with her. Ron has, effectively, married a younger version of his mother. And I can't forget, Arthur Weasley had to lie to Molly about his private hobbies to be left alone from her bossiness and unsolicited opinions. I can't believe that Rowling thinks the Weasley marriage is a good example of a marital relationship, or that she would invent a second-generation version of it, but apparently she does.
Next, Harry and Ginny. Unlike Ron and Hermione, these two are somewhat better-matched, but there is still a fundamental problem with this relationship, and that problem lies mostly with Harry. He has a serious protector complex, and it has made this an unequal pairing when it didn't have to be. Ginny is a perfectly capable young woman. But Harry feels that it is his responsibility to "keep her safe from Voldemort," and breaks up with her. Then throughout the final book, he is shown as worrying for her all the time, as though she were incapable of taking care of herself. For the entire time she's at Hogwarts, she has Neville looking out for her, along with whatever part of the D.A. is still at the school. Harry himself is in far greater danger. It's the exact same situation as it was with Sirius in the fifth book; Harry feels that it is down to him to "protect" someone who does not need his protection, while he himself is actually the person at risk. He doesn't seem to have learned from his mistake that year. Now, protector/charge is a perfectly acceptable dynamic for a parent-child relationship, but again, it's not a satisfying basis for romance. If Harry respected Ginny as an equal, he'd be able to accept that he does not need to watch over her. This, I think, is the true meaning of the adage that if you truly love someone, you are able to let them go. Unfortunately, towards the end of the series, it appears that Ginny decided to go along with this vaguely creepy relationship dynamic. She wanted to fight in the Battle of Hogwarts, and kept appealing to her family, but only when Harry Potter shook his head at her did she give up. That scene troubles me a great deal.
I had hoped, prior to the release of DH, that Rowling would use the Ron/Hermione dynamic to demonstrate to teenagers—girls especially—what a mistake it can be to pair off with your high school sweetheart if he is an immature jerk. I had also held out hope that there would be bombshells to be dropped regarding the horribly mismatched James/Lily pairing and Arthur/Molly. And OK, what we learned was that poor Snape loved Lily, and loved her enough to be honest with her—as contrasted with James, who hid from her that he continued to harass Snape throughout their seventh year, because he feared that she would disapprove. I never saw any evidence that redeemed James. He was a bully with a sense of entitlement, and he lied to the woman in his life about his crappy behavior to her childhood friend, because he regarded that friend as a rival for her affections. There is nothing admirable about this, but J. K. Rowling never acknowledges it. No, instead, she implies in a webchat that it's all Snape's fault for being involved in "the Dark Arts." (Um, hello? Dumbledore clearly studied the Dark Arts. Harry Potter used an Unforgivable Curse as a matter of necessity to obtain Hufflepuff's cup. Rowling, of all people, should not have the black/white mindset that so many fans do about the books.)
Right now I don't know what to make of the fact that Rowling glorifies dysfunctional, unequal relationships that are based on lies and power plays. Or that she sank the one canon-supported 'ship that was built on mutual respect, Neville/Luna. She went through a divorce of her own; surely it would have given her wisdom on the issue, I thought. I hate to say this, but the evidence is overwhelming now that she apparently doesn't recognize dysfunctional romances for what they are.
The following explanation doesn't account for the thoroughly screwed up partnership of Arthur and Molly Weasley, but we don't know the history of that one, or who else may have been interested in them when they were single. But J. K. Rowling apparently regards it as more natural for the bully to get the girl by virtue of his "alpha-ness." It's disturbing, and it's a profound flaw.