The "best looking game" is quite a broad term. For artstyle, it's possible and I agree with your opinions in the OP, but I'd argue that Yoshi's Wooly World might take that honour away soon. For actual graphical fidelity, nope. However I appreciate that ain't the question you're asking.
It's an excellent looking game and, for sure, the graphics add to that feeling when you play the game. But to call it the outright best in all categories is pushing it slightly; not to take anything away from Ori ofcourse.