"No mind" doesn't mean weak mind. It means a completely present mind where nothing but the moment exists.
I find that with some kata I can get into the zone where I don't have to think about the move or the application, which is the same thing that happens during my more successful moments during the hands on part of my training. I will admit that it started happening during sparring first, rather than during kata.
If a student is thinking about their bills, their meeting tomorrow, the 18 principles that will be explored in the course of the kata before they get to them, and how cool they look in their new gi in the mirror...then their training will not be as...useful...as it could be.
One of the important things I've learned from the guy I train with is to be in the moment. Being truly in the moment seems to be one of those things easier said than done, and takes a lot of work to develop.
Let's say that in the big 3 Uechi kata I believe that I know at least one yummy way to use each and every movement in those three forms. Is that enough to make what is in all those forms valid?
IMO, yes! Except I also believe that trying to put too many uses for each movement can break a kata and can give a person too much to think about during the performance.