Ohtsuka is often quoted as saying that the second and third kata in the Naihanchi/Tekki series are 'practically useless'. Could this perhaps be a mistranslation or misinterpretation? I find it odd that he should so easily dismiss two kata created by Itosu and yet embrace the Pinan/Heian series so readily.
Could it be that he considered the other two kata to be unnecessary? That Naihanchi proper was such a complete kata that further variations were not needed?