Controversial, but I think Salah's true level is what we are seeing this season. Whilst he was unbelievable last year, I still don't he's not in the top 5 for his position (CF).
Whilst it's undeniable his numbers/goals are world class, but his ability I still have question marks over; whether he truly is "world class". Or just a really quick player who gets into so many positions because of his speed that it enables him to be an inconsistent finisher and still post up great stats. I think, as a CF, the likes of Kane, Aguero, Ronaldo, Aubameyang are more well rounded players.
But then again, I also think Hazard is a better player than Mo, and i'd consider him "world class", despite never having a truly exceptional (Messi-like) season as Mo did last year, so heh, what do I know, eh.
Alisson, I have question marks over still. He makes top class saves and is a calming influence right now. But whilst he's made some great saves that we are all quick to look at and say "that's why he's worth 67m", equally he's also fumbled a few shots that have gone unpunished. I would put him in the top 10 GKs in the world. But not top 5. Yet.
VVD for me is world class. Easily. Irreplaceable. Top 5. Top 3. Maybe even the best for his position. A mammoth, a leader, a great footballer, and defender. Which is why he's the most important signing for me and Klopp's best buy.