I honestly don't see the IQ issues.
In terms of the number of bad/intercepted passes he makes, I think it's more a result of poor passing technique than a lack of smarts. He did have a tendency to panic when under pressure, but I didn't see nearly as much of that in my viewings of his SHL games.
I still don't think he has the offensive game to become a top pairing defensemen, but I think he's a solid bet to become a steady 2nd pairing guy.
I think there's 2 things about his passing that need to be noted.
1. Power and accuracy. He's not sending saucer passes over guys sticks or crisp stretch passes up center ice like Drysdale, Seider, Byram and some other high end defense prospects of the last few years. A lot of times his passes are knucklers that are hard to handle. In the offensive zone that can be the difference between your shooter getting a one timer off or whiffing on the puck when they get it.
2. Pass placement. He tries to send his passes where guys are currently but not where they are going. Edvinsson is great at skating the puck out of trouble in his own zone but he is bad at hitting his man in stride on structured breakouts, often underpassing the puck and creating a turnover or a puck battle as a result. That anticipation, or lack thereof is why I don't think he has great offensive acumen.
That to me ultimately limits his value. If he really cleans up his passing game then I could see him as a complementary top pairing, 21-22 minute a night guy but maybe not THE number 1. If it doesn't improve then maybe he's just a middling 2nd pair guy.