I think part of it is because they still want to be able to overpower the line of scrimmage to run the ball sucessfully. Ideally you want someone like Bolles that can move his feet to adapt to anything the defense throws at him. I think he'll add weight as he continues to mature. I hope they can draft more like him but they are hard get. As far as your comments about the corners, what I have been seeing so far this year are the refs letting these guys get away with murder on pass interference calls. That's one way for a smaller player to be able to cover the guys you mention LOL