Disclaimer:

Not an expert, however I have watched many games and clips from both these regions, and I may have a unique take on the "upsets" that occurred today in Reykjavik.

First thing first, this isn't the first time either Version 1 or Sentinels have seen "European Style" Valorant. Nor is it the first time they have beaten it. NA has 100 Thieves, who plays almost exactly like how the EU teams want to play, but a little more refined. Most of what NA has brought to bear on this game was refined in the crucible that was, and this sounds weird to say this early in the game's life, the "FaZe Era".

"Predictable" yeah I'll give you that ScreaM, but it is pretty hard to strategize when you've got an aim god like tenz, or Babybay shoving Jett daggers down your throat at point blank range. All of the top NA teams have had to experience and/or overcome this at some point. The two that made it to Iceland, they had to beat it AND "EU Style". Slow steady default driven pick work, is very very effective. But this isn't CS:GO where your boots must stay on the ground except for brief moments when you jump. This is Valorant which provides many options to mitigate the risk of highly aggressive play. I don't think the EU teams (except maybe Fnatic) considered this to be an option in their region, just like the brazilians don't know that they can let go of "w" yet.

So to sum up I think Nuturn is the biggest threat to NA because they've already shown they understand the measured aggression that NA has already had to contend with. It is also not the EU team's fault it's more their regions predilection, to stick with what works and not experiment. NA already had to put down Babybay and the smeag. Just as Nuturn had to deal with the depth of Korean innovative play (Skye in the meta started in Korea). It's not that EU is bad, just there wasn't much depth to their playbook.