I flew with that captain on many occasions when I was an FO. He was most definitely NOT one who slipped through the cracks. Yes, he (and many others hired around the time he was hired at Legacy AA) was forced to spend nearly twenty years in the right seat before finally upgrading, but that right seat time had no effect on his flying ability and command ability. He was excellent in both arenas. He was a good stick, and an excellent captain. I never saw anything from him that made me question his abilities in some way or another.
Why he grabbed so much left rudder as he was about to rotate is a mystery, though. Absolutely a screw up, and he had no idea he'd done it to himself.
I ran into him during a layover one evening maybe five to six months after it had happened and had a discussion with him about this, and asked him if he knew he'd hit the sign and the ground. He said neither of them knew they'd hit anything and the airplane absolutely flew normally during climbout. It wasn't until the FA showed him the picture that the passenger had taken that they had any inkling they'd hit anything at all. He remarked to me how the fbw system completely masked the damage.
So is he losing it, or did he just make some really bad mistake in the moment? Who knows?