Not in the slightest. I think it was @MikeM who already corrected someone's nonsensical opinion on the similarities between the two. Can is a far more technically gifted and skilled player. And a player who can win tackles unlike Khedira. He's a bit of a jack of all-trades, master-of-none from when I've watched him. Would be nice if he had one superlative area to go along with his all-around play.
I feel the same as you about the high wages (mostly offset by the free transfer), and wanting someone better. I'd have liked us to sign SMS, but that ship sailed when Lazio refused to sell him this past summer, if we were even one of the clubs interested. He's way too hyped and therefore expensive now.
Can is a great opportunity and he's young enough that he still has room to grow and improve in a team like Juventus. Worst case scenario is a good rotation player, on a free transfer with annoyingly high wages, who we can sell on in a couple years.