I really am trying to be constructive, but I spent a lot of time thinking after you opened with ‘So technically it can be done.’ Eventually I formulated my actual response based on that, because I do not want my name on a belief I don’t hold.

Do I think that a genderbent!Harry could be written well, if proper care were taken? Absolutely.

Do I think that Rose Potter can be rewritten into something good?

Frankly, no.

Here’s why:
- As I’ve said before, the things you mentioned enjoying have nothing whatsoever to do with Harry Potter canon. This would, I reluctantly admit, not be an inherently incorrect thing in and of itself. However, those changes weren’t actually made to explore and broaden the world, they were made to make Rose more Super Speshul, to allow the nekkid girls, or to create teh sexytiemz. As far as I can tell, the world of Rose Potter shares little more than window dressing with the world J.K. Rowling built, especially as all the characters are wildly OOC. It isn’t fanfiction. It’s original ideas under the veneer of fanfiction. If those original ideas were what you liked, write original fic and wow me with it.

- I don’t think it can be rewritten and remain a Harry Potter fanfic at all. The sporking—more MSTing, as I seem to remember being subjected to those parts of the series which weren’t copy-and-pasted straight from canon--I read indicated that Halcyon left off rather suddenly after chapter 7 of Rose Potter Year 6. More, while the reason for stopping is somewhat debatable, it looks like it’s a shipping rage-quit or potentially even to do with the irreconcilable differences with canon established by <i>Deathly Hallows</i> Even leaving aside the many, many ways the fic broke canon rules before, that is a clear indication it has nothing to do with Harry Potter.

- Halcyon is also known for having plagiarized from other fanfic and lifted things straight out of games he/she liked in a rather blatant manner, to say nothing of the early stages being almost word-for-word canon until it diverges so wildly it isn’t even recognizable anymore.

- Rose Potter is one of the most overpowered God-Mod Sues widely remembered on the internet, and does so in ways that blatantly flaunt canon. For instance, she is able to cast Unforgivable Curses by somehow powering them with <i>~love~</i>--which is in direct contradiction with canon and frankly undermines the emotional impact on the reader. This is to say nothing of the ninja business or any number of other problems.

- My main reason, though, for believing that it cannot actually be salvaged: What do you get if you strip away the inconsistencies with canon, if you excise all the horrifying underage nudity and sex, if you erase the plagiarism, if you make it all fit, if you somehow make the additions plausible, if you remove all the grossly God-Modding extra powers? What are you even left with?

Unfortunately for all concerned, you’re left with Rose Potter.

Rose Potter is a horrible, horrible person who starts murdering people at the tender age of <i>eleven</i>. She carves words into Ron’s forehead after flinging him around the room. She actively learns dark magic, she is eager for genocide—in short, she is a terrible person who is more akin to Voldemort than Harry Potter.

So then what happens if you take that personality away as the last vestige of Halcyon’s screw-up?

You get… well, genderbent!Harry Potter.

In conclusion: you can write genderbent!Harry Potter. You can try to add the elements and keep anything recognizable as Harry Potter's world. You can write unexplored parts of the Harry Potter world—go ahead, explore the United States, but then it’s not Rose Potter anymore. You can original fiction with druids, necromancy, and magical schools.

Girl Who Lived itself, though? No. No I don’t believe it’s salvageable, and I don’t know why anyone would try.