You do realize he played a massive role in their league title, right? Pretty sure he played all matches except for like two. Did a damn good job.
And so did Vardy...
What exactly is your point?
He's had 1 good season in his career, as a 25 year old. He's basically the midfield equivalent of Ogbonna. A 1-hit wonder so far.
Could he go to a big club, and become a consistent world class player? Yes. 100%. But until he has shown this level for multiple seasons, I'm going to hold off on acting like he's some world class superstar, and the answer to all Juventus' problems.
There's also not a chance in hell he'd start over any of Pogba, Pjanic, Marchisio, Khedira. Of course, the last 2, when healthy.