it's more about gently mixing the plants and letting them grow in and compete for light
Amano wants to give a natural appearance to his tanks, with nothing too manicured or distinctly heavily bordered. I remember a big tank from one of his NA books where he let glosso just take over the whole thing, I'll see if I can dig it up. Your thread is making me want to do an Amano throwback tank now!
this layout is similar to the 90P in John's signature, particularly before the introduction of the H. Japan; I know this because I purchased it. The tank looks significantly different now but I always admired John's work in person and he's the main reason I am now interested in planted tanks.