Okay, lets look at this scenario. What if you had a bunch of guys that fought without any understanding of methodology. Lets say their methods were simply trial and error and they fought everyday and tried to replicate success.
Eventually they would reach the conclusion that they needed to figure out how to break things down into a more systematic approach. It would involve some sort of kata.
Again, the issue is not that kata is not helpful, just that alot of kata that is practiced out there is simply alot of stuff that no longer can be articulated back to something that allows it to be a systematic and progressive system that someone can even understand.
This is what I mean by "one person tma type kata". 2-person katas are different, every style does them, they often just call them "drills" and the moves make sense. If the moves in the single person kata were all real fight moves or done specifically for body training(like internal conditioning) that would be a different case. It would be like shadow boxing, except you would not improvise. As an example for kickboxing a one person kata could be :Jab,jab,right,jab, move back, move left, shin block, front kick,etc.
That would make sense to me. And to be clear about the non fighting conditioning katas, it needs to be clear, how,why and for what purpose. Kata may have body training in mind but if no one is able to teach it the proper way, who cares.