In real hockey/NHL, sure, a player can have a designated defensive zone, but you don’t just stay in that zone. Generally there’s a man-to-man thing going on which does require you to move around outside of your zone.
I get that. It's not realistic to stay in position 100% of the time. And normally, teammates cover each other. We're talking about how the AI behave though. Which is identical on both sides. The big differences are how the humans are controlling their players as well as which strategies you have set.
The AI on both sides are the same though. With the exception to varying overalls.
Also, my comment was more direct towards online play in WoC. You're playing BaP and are obviously more reliant on the AI. Hopefully, we'll see them improve more over time.