When I first got my Amano books, I was disapponted that they were so "vague". Like most people, I wanted a step-by-step instruction manual. I wanted his talent to be broken down into a definite science that I could digest. I have learned that he would have completely failed if he had tried to make those books manuals. He would have been accused of giving false information, being unreliable, etc as people would have followed his steps and never gotten identical results.
I agree that aquascaping is analagous to painting, but I would take it a step further and liken it to sculpting, not of stone but of clay, since it has a dimensionality and is always ready to accept changes, additions, or complete recyclings. Of course, it's even more complicated than that since it changes even if we leave it alone and do nothing.
Like all the above art forms, examples are probably the best tutors we can provide and immitating those examples are probably the best lessons we can hope to recieve. I have some diagrams of how various Amano aquascapes were planned, but I don't think there's any way to effectively convey how they were conceived or nurtured without a one-on-one apprenticeship with someone that has done it, and even then you are only being shown the motions that were gone through to achieve that particular aquascape with those particular plants and under those particular conditions. The minute you go home and used your own water you are breaking the paint-by-numbers method somewhat and subjecting yourself to variables that you would have to experiment with to learn to control.
I think taking a strict step-by-step approach is sabatoge. We can glean knowledge from the experience of others with some things, like calculating how many seconds are in a century. You don't have to actually live 100 years and keep up with the passing seconds to gain that information, there are tried and true formulas that you can follow. Aquascaping, or any creative form, is not something that can be recorded and passed on with numbers or blueprints. I think pictures, design theories, and general planting techniques and general care of specific plants are the best and only help any of us can expect to get. Knowing how to put it all together requires talent, time, experimentation, and a long long series of failures. You either get lucky or you do everything wrong over and over again until all that remains is right. I hope I accomplish it through the latter rather than the former, as the latter will give me what I need to be able to adapt and create new things with higher success rates and more intuition.
Aquascaping is a personal and original form of balancing all of those things in unique and creative ways. Your aquascape is as much a reflection of you as your taste in cars or any mirror.
IMO, taking any approach other than experimentation and observation will be very limiting and very frustrating. It may make getting to a basic level easier, but it would involve skipping the important realizations and experiences that are necessary in reaching the higher levels of the form.
Knowing general values for parameters we can control, basic plant care, then observation and experimentation are about the only ways I can think to do it.