I would suggest you read "THE CAMERA" by "MR. ANSEL ADAMS", you don't have to read the whole book, ...the FIRST CHAPTER will do! It's called "VISUALIZATION" and I read it when I was very young... It really helps if you take advanced knowledge into account when you find you have a passion on something (like photography for example).
I don't think its rightful for you to call principles of the masters of photography "narrow-minded".
Just because Ansel Adams worked in a certain way does not make it a principle. It's nothing more than a methodology that suited him and his subject matter. Though you can certainly learn a lot about photography by studying his work processes.
As you for statement saying an artist should pre-visualise an image completely before taking the shot to be art is such a really daft statement. In fact I'd I'd say that may be useful advice for beginners to consider [as a learning tool], but once you know what you are doing you can shoot in many, very different ways.
When I used film I carried two cameras, one with B+W and one with colour and I knew what I'd get when I shot with either as the options after developing were quite limiting compared to toady's way of working. Now with experience I can take a shot as I simply know there is a good image there or simply work quite spontaneously, but it is not until I get back to my computer do I then draw the image out of the RAW file and how it ends up may well depend on my mood that day and when I revisit it, I may do a very different image again.
One of my favourite images works well as a B&W or as several very different types of colour shot. I captured this image by without over thinking things and only did this particular shoot as an aside and after getting a shot I had pre-visualized, which is why I was in that location and decided to make the most of it and so shot someone else too.
I don't have to preplan what I'm doing when riding my bike over rough terrain as I'm well practiced, same goes for photography as with experience your skills need less conscious thought.
BTW an awful lot of art and creativity comes from happy accidents. The artistic skill lies in being able to recognise when a mistake is gold to be mined.