Board Thread:Spoilers!/@comment-1916997-20151207200642/@comment-26443838-20151208004506

A&E mentioned why the had Hook die, and I quote:

Every season, we try to evolve Emma a little more. She started as a non-believer with walls up who wouldn’t even admit she had a child. [Now] she’s got her family, she’s realized Storybrooke is her home, she’s accepted who she was. She finally opened her heart up to Hook. She finally embraced falling in love, and unfortunately for Emma, everyone she’s ever loved died, and she just didn’t want to see that happen again. So we liked the idea of, what happens when Emma is confronted with the idea of having to let him go? Well, she couldn’t do it. She turned him into a Dark One, the one thing he hated. But their love won out and she ended up having to let him go. But we realized she didn’t as she echoes her father’s line, “I will find you. I will always find you.”

I guess they are trying to make Emma evolve a little more (like they said) and let someone rest in peace and learn to move on (kind of like growing up in the inside, be mature and more importantly enjoy the company she still has). I don't know if that is the case, but it is kind of like they said by her admitting she had a child, getting her family again, realizing Storybrooke is her home, accepting who she was.