Why do we need to exaggerate who he has been playing with? He wasn't paired with Wahlstrom for any real length of time.
Barzal is a unique talent with value, but he's been difficult for players to have chemistry with during his time here. Eberle, Horvat, Lee, Nelson, Palmieri, etc. are all 30+ goal players and he hasn't managed to find consistency with any of them, except for perhaps Eberle. Their style of game also didn't translate well in the playoffs after the first round. His uniqueness makes him difficult to play with because he wants to hold the puck for extended periods of time and refuses to use his teammates in more routine plays, opting instead to control the puck himself and keep looking for better opportunities. That translates really well to the advanced analytics for him as an individual, he's maintaining possession, he has the puck on his stick, and when there is success he gets points. The problem is, what exactly are the rest of his teammates supposed to be doing when he does these things? There's a limited amount of space in the offensive zone and if you're not using your teammates to move and manipulate the defense then there isn't much that will open up. Add that with his refusal to shoot the puck and his unwillingness to go into the dirty areas to create space for his teammates when he doesn't have the puck, you end up with a difficult player to develop real chemistry with.
He's not lacking in talent, his talent is exactly why he has value, and that's why if you can swap him for an easier player to play with the team might see better results and provide more flexibility. You only move Barzal for a player who has the potential to be better than what he is, but there's obviously a risk in doing that. The team isn't haven't success with him, they can have the same result without him.
As for the strategy of defensive minded compared to offensive minded, there's truth to that. The roster hasn't been good enough to play the open style for nearly his entire tenure here. They also haven't been able to acquire the players necessary for that type of system, how are they suddenly going to do that now? It's going to be a while, and if we're re-setting I'd collect valuable assets for Barzal now rather than later.