Trial and error is a valid form of game design. People act like the game doesn't tell you to shoot at every wall, floor, and ceiling you see, and then immediately present that very gameplay concept to you and then use it repeatedly all throughout the game.
It would be bad design, if the game never indicated to you to do it. But it does. The game moves at such a fast pace and Samus can fire her shots so quickly, you can literally discover all the hidden paths on the fly with very little effort. By simply doing what the game tells you.
Indicators something is breakable, basically gets rid of any sense of trial and error. Any sense of wonder or discovery. It's just telling you what to do. Some people absolutely LOVE that. They prefer the path forward by clear and concise, easy to grasp, and the game just guides you quickly through it. But, not every game is that way and many games do not make it obvious certain things can be interacted with in any way. Though, in every case, the game told you at one point to interact with things in that way. The player not remembering to do that, or taking that instruction and making assumptions "oh it told me, but I never used it until now" - is factually incorrect. But that's life. The game at every turn where you break a wall/floor/ceiling has SEVERAL indicators that it's highly likely that floor/wall/ceiling is breakable. Instead of the wall/floor/ceiling itself being the indicator (because that's very obvious and takes away a sense of discovery), the placement of enemies, the design of the level, and the fact there is clearly something on the other side are the visual queues presented.
David just would rather do away with that, and just have some cracks or light or something that just tells him what to do. It's a different type of design to what he prefers, but the game DOES visually indicate you should try shooting at things. It just does it in a more fluid way that lets the players use their brains.