You say it like it's a bad thing.
Yeah, KHL is so weak that when a middle-six KHLer like Tsyplakov is moving to the NHL he becomes just a middle-six NHLer.
Seriously though, I think when answering the question in the OP Nikishin is likely the correct answer, however it might be not that easy to determine a top 5, as indeed there are interesting players not only in the KHL who might be totally NHL ready already at this point.
My logic is the same age players from other leagues are either not good enough or already NHLers. And younger players are just not there yet.
I mean look at NCAA, who's the leading scorer of the league right now? Nashville's 7th rounder Aiden Fink. If you ask hfers about him, i'm pretty sure 90% will answer "never heard of him", and such stats don't usually mean a lot anyway.