My own opinion is that theory must not screw up the practical use of martial art. If I see a better way of decking somebody, I do not want some theoretical point getting in the way of that. Let the theory catch up with the facts.
Martial Arts is not something based on theories. Theory is based on practicality.
Practical practice and application always comes first. Theory is a way to study practical things and to organize practical knowledge so you can have tools to pass on your own personal knowledge to other people.
When you learn playing an instrument, the practical practice, what you practically do, is what is important. But your teacher helps you learn, step by step, in an organized manner. Of course, you can just take an instrument as a piano and start pressing the keys randomly and hope that you will eventually learn to play. You could do it all your life and hope to do it. Or you could use the theory built up by generations of musicians and actually learn fast how to play.
Now, if you try learn the piano and believe that you will become a better musician by reading old documents and history about old instruments you’ll have a problem. If you just want to become a better musician you should spend your time playing and practicing. If you are interested in culture and history you don’t need to play, though having some practical knowledge might help you to understand the history better.
The problem with martial artists as I see it is that they believe being a historian will help them to become a better martial artist. This is mostly many generations of teachers fault because they teach the value of tradition and focus much on tradition.
It would do Martial Arts good to throw away all uniforms, greetings, bows, grading systems etc. and only use modern practical language. You can still learn about history and culture but to keep it clearly separated from practical practice.
The downside is that martial arts teachers would lose all of their income because what people want to learn is in fact not something useful for fighting, but to wear uniforms, bow to a teacher and to get a grade and a colorful belt. etc. They want to be historians and not practical players. A traditional martial art school is mostly more like a medieval age club or society. If you just want to fight, why not do MMA instead? Because who can believe that TMA can be useful?