Learning a technique based teaching system seems to me to be like learning to be a musician by learning a bunch of songs instead of the full syllabus of music.
Learning principals and basic fundamentals through well developed learning sets (kata) and exercises have always seemed the best way to learn for me.
By learning kihon dosa and kihon no kata and internalizing them, we become able to intuitively create variations that fit what's necessary in the moment. Then we can always return to the kata as a teaching tool and experimental base for expanding our knowledge.
Randori then teaches us to use our creativity in random and (often) surprising ways.