Agree to an extent.
I think it's a mix of both. Does the system get the best out of him, and is Gylfi good enough (on his day) to have the system built around him. I'd have to say on that last point, as much as I like him, not for me.
But, we do need a system that helps get the best out of him because he's our best creative player. I don't see how there can be arguments with that. He creates chances - as he should - and scores goals.
Now, would it be better to move him into a three, so he can have more of the ball - because the accusation is in that second striker role he doesn't 'do enough'. You'd then have to make sure the front three was a proper three - not a central striker isolated inbetween two wingers stuck out on the touchlines, with no movement.
Or, is it to stick with him in the 2nd striker role and try and get back to the form of our decent run. For that I think Richarlison needs to be central and we need to have him dragging defences around, opening up space for Gylfi and Bernard to operate in.