Case is mobile, but he runs around a lot because he lacks the height to see sometimes, lacks the height to get a throwing lane, has poor field vision and locks onto a guy. I don't think anyone knows for sure if Mannion will do better or worse. I think he's worth a shot as our season is on the brink (maybe over the brink). If they say he has a much better grasp of the offense than Goff, which he should, why not go down swinging as they say. He's also got a much better arm than case and might actually be able to run play action and stretch the field with more than arcing balloons from ole noodle arm.