It might help us understand you better if you defined what you mean by TMA in general and traditional karate specifically.
Please see my reply to "ZERO" over @ "MMA and Similar Arts are not True Martial Arts." @ Page 3.
Here's what I tell students (or instructors) that are willing to take input. Simply, IN TRADITIONAL KARATE, MENTAL DRIVES PHYSICAL. Just as you state, the physical expresses the action, but it is the mental capability that powers that physical expression. PERIOD.
Yeah ... can you clarify how "mental drives physical" more in what you call "traditional karate" than in any other art? Can you break down what that even means?
Let's look a bit at how "mental" and "physical" work in
any art for
any human being in the real world:
1) You practice various basic physical skills and movements with conscious awareness. With sufficient repetition, you build new neural pathways in your brain for the execution of these skills and movements. Once fully formed, these pathways become automated at a level below your normal conscious awareness - you no longer have to think "push off my rear foot, rotate my rear hip forward, tighten my core, transfer the rotation into my shoulder, extend my arm, tighten my fist, etc". You just think "reverse punch" and those neural pathways fire off and send the signals to make your muscles execute the punch.
2) You consciously practice higher level perceptual and tactical skills which may make use of the previously mentioned physical skills. You might practice getting off angle when your opponent punches and punching back when he drops his guard. With enough repetition, the details of this also become automated below conscious awareness. You find yourself starting to move off angle as your opponent begins his strike because you already subconsciously recognized the "tell" where he dropped his shoulder or changed his stance slightly before punching. When you strike back, you automatically aim for the targets that your opponent has left uncovered. All this happens due to more complex neural pathways that have been developed through practice. You don't have to consciously think about it any more than you have to think about the shapes of the letters on the page when you read. (If you are still consciously thinking about these elements, then you are probably not reacting fast enough to execute these skills in a real fight.)
3) You train to handle certain neurochemical effects of a real fight - adrenaline, fear, anger, pain, fatigue. This involves a highly complex interaction between your brain, your muscles, and your endocrine system. With experience, you learn to get better at overcoming the deleterious effects of these reactions and utilizing the positive effects.
4) While all the above is going on, you are hopefully building physical strength and endurance as well. this is primarily a "physical" process (muscles, tendons, bones, circulatory system), although there is some training of the neural pathways involved in pure strength training as well.
5) When it comes time for the fight, your conscious mind is in charge of the big picture - "keep an eye on the guy in front of me, circle for the exit, but don't lose track of his buddy that's hanging back" You might devote cognitive resources to the elements mentioned in #3 above - "relax, keep the breath calm, don't get frustrated". You might make conscious tactical decisions - "his buddy is cutting me off from the door - as soon as he gets in range, blitz him with punches, then disengage and run."
All of this is mental (the brain) driving physical (the muscles, although the circulatory and endocrine systems get involved too). (Technically, there's a complex feedback loop going on between the different systems, but let's keep it simple for now.)
If by "mental", you mean the
conscious mind, then it gets a bit fuzzier. The conscious mind is like the CEO of a vast company, sitting at headquarters receiving quarterly reports and setting out strategic plans. 99.99% of what is going on in the company is beyond the executive's direct perception or control. He has to just trust that the various departments are doing their jobs. If your conscious mind is trying to micro-manage your body on the details of how to throw a punch during a fight, then you've already lost.
So, to return to my question, how does any of this work differently in what you are calling "traditional karate" (Shotokan & TKD & your secret art) versus any other martial art?