Should alternate endings exist?

Some of you may have seen the news that J.K. Rowling supposedly almost killed off Ron. While this would have definitely made for a stronger ending in my opinion, I can see why she pulled back. You don't want to risk pissing off your fans, unless you're someone like Joss Whedon and killing off Wash in Serenity is apparently no big deal.

This relevation led to a rather interesting discussion with my wife: Is it ever a good idea for authors to divulge the endings they didn't write? Wendy thinks that Rowling does her fans a disservice by revealing what could have been, because Harry Potter fans are so attached to the characters that to suggest the story could have unfolded any other way is to make the whole affair seem somewhat arbitrary.

My first impulse is to disagree, and say that offering a glimpse into the author's decision-making process does no damage to the finished product. But upon further reflection, I'm not sure what purpose it serves to even discuss the different possibilities. An ending is an ending, and you can only pick one. Sure, she could've killed Ron. She could've killed Harry too, or the entire Weasley family, but she didn't. Writing is the process of whittling away all the different story possibilities until you (hopefully) end up with the best one. While I'm on record saying that the Harry Potter series should've ended differently, I respect the author's decision to end it the way she did, and appreciate that she must have been under enormous pressure to deliver a satisfying denoument to those hordes of weird, obsessive fans. That doesn't mean I think it was a good idea for her to open up about what other endings she contemplated. Wendy's right -- it does seem like something of a slap in the face to fans who take this stuff so deadly seriously.

I doubt that Rowling intended any malice with her statement. More likely she just enjoys the attention (Dumbledore is gay, anyone?) or somehow still doesn't fully understand the power her work has had over people. I'll put it this way: If Shakespeare had come out and said that he almost let Romeo and Juliet live, would it have given any of us a deeper appreciation of the actual work?