Replacing a ninja-like Sheikah... with a ninja-like Sheikah?
How diverse...
The word "better" implies subjectivity and the word "irrefutable" implies objectivity or factuality. Can't you see the blatant contradiction here? I can't take you very seriously if you have contradictions in your argument.
Again, removing Sheik and replacing her by Impa is not going to inherently better Zelda, no matter how deluded people think it may.
The majority of the Smash fanbase wants Sheik back. Like it or not, she's become a staple of Smash Bros., appearing in 2 out of the 3 Smash games released so far. She's also fairly known among the Nintendo fanbase, if the cameos in Tekken Tag Tournament 2 and Scribblenauts Unlimited are any indication. Should I even mention Ocarina of Time being remade for the 3DS?
Removing Sheik (or any veteran character) would alienate the fanbase and Sakurai knows it. That's why I simply can't believe the idea of Sheik being cut and Impa inheriting her moveset. It doesn't make sense and contradicts Sakurai's wishes.