I like both Kate and Jack, too. I've never been entirely sure why fandom hates them SO much.

The other theory I've heard is it's death that makes you closer to your alt!self. But I think I might like this one more, since it does seem like some people at least sort of remember (though not consciously) the island. And I agree that's probably why Claire trusted Kate so much. (Because that really bugged me at first, too, haha.)

And I so hope you're right about Jack being a hero at the end. I want that for him so badly!