True that triggers are beneficial, I think the placement of them is somewhat flawed. The trigger is right behind the button, which is a big problem for people with big hands like me. The trigger kept getting in the way when I was trying to press the undersized button. The inversely symmetrical controls may be easy once you get used to it, but to me, it's equivalent to learning to write with my left hand. Anyway, the reason why the PSX controllers are colored symbols instead of letters, is because of the fact that it stimulates a different part of the brain, which is more recognisable. I remember my SNES being more oriented with the layout of the buttons, rather than the labeling of them. I knew by heart where the X, triangle, square, and circle buttons were two weeks after I got my PS2, and when I was in my SNES days, I always had to think of it for a bit if the buttons were referred by letter (with the exception of L and R buttons).
