The practice of goju-ryu karate has always involved extensive body conditioning exercises. Starting with kotekitae, goju-ryu people then practice with chishi, kongo ken, and nigiri game. And of course sanchin kata is considered the essense of the system.
Plenty of traditional karate systems don't utilize these exercises however, and I don't necessarily think they are deficient for it. They just have different focii. Consider shito-ryu. The founder, Kenwa Mabuni, was a contemporary of Chojun Miyagi, the founder of goju-ryu. Mabuni was certainly considered every bit the karate man Miyagi was, yet he did not see fit to add there exercises into his curriculum.