Yep, he's by no means an upgrade. But if I had to choose who I'd rather have in a team, it would Guthrie over Gibson any day.
Why? Guthrie contributes absolutely nothing. He's a somewhat neat passer, but not to the point of being a player who is great at retaining the ball. This is the extent of his skill. There is little else.
There's something in Guthrie that I just see which is better than what I see with Gibson. You mentioned Guthrie's passing which I think is a lot more than what Gibson can do at the moment.