Again, this was my point.. and remember these are just my own opinions.
Im very happy we have this discussion, because i love to discuss gameplay elements so i know how other people thinking about gameplay elements and my design choices. around 30-40% of good gameplay ideas i had in the past came from discussions.
But this is a game design issue. If you present a room where the player can not instantly see what he is meant to do.. 99.9% of the players will instantly hit the "show me the hot spots" button. This is retarded, and for me defeats the point of a puzzle game. When designing the game it is up to the developer to make the scene "readable" so he knows to click on the ash tray.. by it eather being the answer to a clue already given or obvious to click on.
If your game has the "4 pixel" item you could never find without the hint system, it is instantly bad design, i totally agree with you but you have also to think about the fact that an adventure is not a pen&paper role playing game.
So, as a designer, you have to choose all possible solutions and interactions.
The hint system is not for the designer so he can create unreadable scenes, i absolutely agree there, but it reduces the instant "pixel hunting" aspect of the game for people who dont want to do this.
The first thing you do in a adventure if you visit a new scene is: you move the cursor through the room if there is anything interactive there. So if the designer shows all interactive objects in the room, he will give you more time to solve the real puzzle there.
I dont know if you ever played text adventures, but the first thing you do in a new room is very similar: you type "look" and the game tells you all interactions there or it already tells you this automatically at entering the room.
"you are standing in a wide floor. To your left is a desk with paper on it. In the middle of the room is a nice green carpet on the floor. To the north you see a cracked window. The exits are south and west."
So all you get is the option to get a room interaction description.
If the game "puzzles" are based on finding all room interactions i would say the game designer already did a bad design choice, because it completely destroys the flow of the game.
The instant teleportation also is not an excuse for implementing back travelling. It is there to enhance the flow of the game. Its most likely that if you have a problem with a puzzle, you will revisit all old scenes if you find some item you missed, at least that is what I, my friends and my parents do (ok, at least not my mother, she already prints the walkthrough before she starts the game, so she has by default no puzzle problems).
If you dont use some "hub system" like a city map in your game and most scene is 2 or 3 rooms deep like in Gabriel Knight or Broken Sword, you will get instantly heavy back travelling.