Chalamet's Paul seems to lack the unshakeable self-confidence of McLaughlin's Paul from the few seconds I saw in the trailer. Paul should not wince during gob-jabber. Nor should he grimace in pain or fear in battle.
People are much less serious and more affable, gregarious than they were even 50 years ago - and it comes out in everything, dialogue, disposition. You can tell immediately, before they say a line, it's how they stand, and in their faces.
Go and look at 'Grand Moff Wilhuff Tarkin' - the big baddie from from Star Wars who very confidently dismissed and told off Darth Vader ("Enough of this. Vader, release him!"). This guy would embody the quasi-aristocratic head of say, the East India Company Governor back in the day. A kind of cold, callous, calculating CEO, who's involved in war, blood, serious repercussions etc.. English stage actors have the ability to do this. Most of the cast of Lynch's Dune were well trained actors, and Kyle MacLachlan just had a very special air about him.