I disagree completely. The caveat being he was CAPABLE of preparation but exceedingly lazy. He only bothered to prepare for one or two games a year. Most of the time he didnt bother and was happy enough to just burn the first half, go into the locker room down a score or two if he had to and make adjustments.
He was a well above average, though not quite excellent, half time adjustments coach. I sometimes struggle to think about anything he is good at, but this is clearly his strength.
He could also, if forced by a superior or by circumstances (like Trash), call a pretty good passing game or a mediocre conventional run game (think Latsko era).
It's sad really. He was capable but was too wrapped up in a middle school level option run game that doesnt work and genenrally just too lazy to use his talents in an optimal manner.