It seems to me that this thread addresses two main topics:
- Adventure games “narrowing down” when the player approaches the end and the world has less things to do/take/interact with.
- If point-and-click adventure games are mainly defined by the story or by the puzzles.
About the point 1, I think that it’s true that the world can feel more empty when the player has done most of the things that were required to proceed. I don’t think that this phenomenon is necessarily a bad thing, though, because in my opinion it was never a goal of adventure games to make the players believe that they were in an open world.
In point-and-click adventure games, there is a static tree of paths that has been designed by the authors and the player has to traverse this tree to reach its end. This structure can usually be traversed in more than one way and, from this perspective, this is the feature that makes adventure games non-linear, but when the tree is traversed the story and the puzzles are consumed by the player and towards the end the quantity of things to do has been reduced. I think that this “consumption” is an intrinsic property of adventure games.
Is this bad? It depends. For me, the emptiness of the locations that I’ve already explored and “used” helps me to understand that I’m approaching the end; it’s a way to feel the progress that I’ve made. Personally, I wouldn’t like to go back to already explored locations just to do “random more stuff” if this stuff doesn’t help me to reach the final goal.
For example, in Thimbleweed Park, Chet appears at the intersection of Main Street with B Street after a while and the presence of a character who wasn’t there at the beginning makes the place more lively and believable, but this happening has a purpose and it’s necessary to advance the story. Adding red herrings or useless objects to already explored locations to “renew” them just for the sake of renewing them, would be in my opinion a misleading change for a player who has a goal in mind and who wants to proceed.
About the point 2, I agree with @N_N when he says “It’s difficult to be reductionistic about works of art that are greater than the sum of their parts.”.
I don’t feel that dissecting an adventure game into its parts and trying to establish which one of them is the main feature of this kind of game makes much sense. Even if it was possible to reach a definitive conclusion, I have the feeling that we would do a disservice to this game genre, that has become famous for flawlessly mixing story and puzzles so that they are inter-dependent.
This opinion of mine is related to another topic that I’ve addressed in other threads: there is not a strong and shared definition of what an “adventure game” is. Some of us think that puzzles define this genre more than the storytelling, while other people think differently. The point is that… definitions (and strict recipes) are not so important, in my opinion. (unless you need them to understand what other people are talking about)