Indeed. If the defense has gaping holes because of graduation or injury, it doesn't matter. The head coach is supposed to see those things coming and prepare (as in recruit) for them, especially a head coach making $1MM a year.
Having said that, I don't see Hud getting canned at the end of this year because I believe our offense will win enough games for us even if the defense never comes around.
Looking forward I'd much rather see our AD structure the next head coach's pay package based mostly on performance bonuses. Crappy year, crappy pay. Exceptional year, exceptional pay. It's done all the time with salesmen and upper management of businesses, why not with a head coach?