I really don't think that's the case at all. EJ's had some terrible miscues to start the season. Not horrible, but not top-pairing either.
And that's the other side of the coin--I think Makar and Z have been even worse together than Sammy and EJ, those two aren't on the same page at all. Makar plays a much cleaner game alongside Girard. And yes, I know that pairing isn't exactly perfect, but it more than makes up for its shortcomings in terms of pure puck dominance. Conversely, Z and EJ have always been good together. I get it makes for two wildly different pairings, but I think those would work a hell of a lot better than what they're trying now. And it shoves Cole onto the bottom pairing where he really belongs.
I don't think EJ's been perfect, he's had a few miscues, but I think the positives far outweigh the negatives so far this season.
I've always liked the Girard-Makar pairing. Even before they were paired together the first time. They're both so cerebral, it makes up for some of the risks that go with pairings like that. So I don't have a problem with those two playing together.
I actually like the way Bednar and Pratt rotate the D pairings within games though. I think they have a good handle on when they need a more physical defensive pairings like Z-EJ, and when they need a more more mobile and creative pairing like G-Makar to create offense.
The main concern with that approach is that guys will be too unfamiliar with the new partners, and make mistakes, but I think they have the D practice with everyone often enough, where they look comfortable with multiple pairings.
I'm not sure if they kind of pioneered it like Roy did with pulling the goalie early, but I hadn't seen it utilized to the extent they do in the NHL before they started doing it. I notice other teams doing it now though. Maybe everyone started doing it around the same time.