Concerning JKRowling's attitude to slash fanfics, I think she actually made a few winks to those fans in the last two books. The 6th Book, Malfoy had a big part and Harry was completely obsessed with him and at some point, it was told that he enjoyed having power over Malfoy (when he realized Draco was in the Room of Requirements and couldn't get out because Harry was there). I laughed at that because I thought it was JK's way of a wink to those fans who love the Harry/Draco slash. And in the 7th Book, the scene where Harry saves Draco has the latter holding onto Harry for dear life, can you imagine that on film? It's nothing"gay" but has Draco ever held onto Harry like that, ever?
And also, Lupin's werewolf status is basically a play on the "homosexual". He is fired from the School in Book 3 (I think) because parents were "outraged" that a "werewolf" was teaching their children.
Finally, Dumbledore and Grindelwalt (sp?) relationship can be seen as ambiguous.
So, no, I don't think J.K.R. is homophobic at all. She may have her own vision of families, romances, and stuff, but I doubt she dislikes the slash fans, etc. Also, the first 4 books, at least, are aimed at children. This is, after all, a children's book series, though the last three are of a more mature level, but at the base, it is still a kids' book, so having themes such as homosexuality, or even bisexuality explicitly in the text would cause censorship and stuff. It is a sad fact of today's society...
Anywayz, I did enjoy the book. I really like the character of Voldemort, because of his rich background especially. I loved book 6 because of the backstory we got of Voldemort. He's a despicable character, and is pretty much the Hilter of the Harry Potter world, but a well written character nonetheless.
Rowling did hint that she might write more Harry Potter stuff, but not anytime soon and it would be for charity.