Yeah he's a great poacher but big clubs will always feel like they can do more as a team if their striker was a complete forward. Haaland outside of the box is useless, apart from making the runs in behind. It's not his game, which is fine, but the truth. City is a team who don't need a poacher. They don't need a player who will batter the small teams. They do that without him. The fact that they have fewer xG and fewer xPts than at this point last season where they played without a striker says a lot. Haaland was never a player who was going to make a difference in the league for them. City will walk the league most seasons, this season they lost some motivation so they are more inconsistent, with or without Haaland. Their league output is the same with or without Haaland though. He can score loads and break records while the team goals is just funneled instead of spread out. That's the difference.
His impact will be shown in the big games ... Yet in those games there is less room to play, so he has been struggling in some of them. We'll see how he does in the CL. But he isn't a complete striker who is also a great goalscorer like Lewandowski, Benzema, Kane. He's a poacher who is useless outside of the box. And at that point it becomes a balance of just how many goals does he need to get to outweigh what he doesn't bring. If his team is scoring more and doing better as a team than before he joined, than fair enough he's on the right side of that line given all the things he doesn't provide.
Other teams he'd fit in far more, but City is one where he doesn't really make them better.