Yuno was probably the second or third i ever saw in an anime.
I think she was the only reason why i tolerated, rather enjoyed mirai nikki. Without her and Yuki's very obnoxious character, i am sure i would've left the series in the middle.
That aside, she was lovely, as Rey-senpai said, "she's kawaii and she have kawaii pink pigtails stained with blood"!! I love her looks and character.
Your synopsis and explanation of her character is perfectly fitting and i agree with it. Reading your thread reminded me of one of the best yandere ever, loved reading this, Thank you!