Karate is Kata. Kata is Karate. That’s my own opinion, of course. An element of justification for this comes in the principle of alternating body mechanics: fast and slow, hard and soft, or compressed and relaxed. In Kumite we see these, just as we do in Kata. There are times when we need elements of speed, followed by compressed muscles, followed by relaxation. Then there are times when we see slower, softer, more deliberate techniques, sometimes followed by muscle contraction and relaxation again. These are elements of the complementary early-day karate styles of Shorin-ryu (forms linked to natural movements and natural breathing, and Shorei-ryu, characterized by strong, rooted movements.
Yin and Yang Perhaps? I see Yin and Yang, in part, as the complementary (not opposing) forces of hard and soft.
In my own training I tend to go all Shorei and end up looking choppy and over-strong. I am constantly reminded that Shotokan is unorthodox in some of its principles in that being too tense reduces your speed and fluidity, and yet being too relaxed lessens your power. You have to find the balance, and there is no better way to do that than find the right tempo in your Kata.
A never ending learning process, this karate stuff!