Very good points,
However from the humble opinion of someone that has watched Cro Cop since he fought Andy Hug and followed him into MMA.
I believe Cro Cop's prime was in 2003, his downfall i will always see as giving up on K-1 that year when he was at the best he ever was striking wise, and as he gave up K-1 he no longer needed as such diverse striking especially with his combinations as by 2003 everyone in MMA feared him enough for Cro Cop to get away with just using his boxing to set up either a liver kick or high kick.
His overall MMA game improved but the level of his striking degraded and by the time his body began to slow down he wasnt nowhere as good as he once.