Here's the same trailer with commentary from the showrunner, and I feel more reassured about the 3 oaths and their not being dumbed down.
Click to view
And I do want to stress, I see several things I like in the trailer:
The racial diversity (which is there in the books)
The fact that they are not dressed "high medieval"
The handling of the Taint, (which they are calling The Corruption)
Fal Dara & Tarwin's Gap don't look quite how the book described them, but they do look great, and I love that Lord Agelmar and the men have their top knots.
Aiel fighters are fucking badass, and that guy in the cloak ... I'm pretty sure I know who that is and it fills me with joy if that is so.
Narg ... who doesn't look exactly like how he looks in the books, but I have hopes we'll get his iconic line.