Designing an inventory system is a lose lose situation. There is no contemporary way, measure or thought to do it exceptionally well. As soon as someone stumbles upon a clue. Someone releases a game which knocks us back a few paces due to an inferior inventory. I'm mostly writing this for my own thought process. I chose here as a place I could potentially get some feedback.
Let's start with an idea. Ergonomically the simpler something is the better function it will perform.
Let's look at adventure games, as this is a good reference point to where ergonomics did more harm than good. Maniac Mansion and say Space Quest IV. Both wonderful games of my youth. Half the puzzle was figuring out the natural game progression half the puzzle was figuring out the grammar.
SQIV did it via pictorial verbs while Maniac Mansion did it via written verbs. Both had pretty much the same interface. Then some genius figured out that the verbs were redundant and all you need is one verb. The Use button. However, we all know the best word to use universally in place of any other verb is fuck. Which is exactly what happened to adventure games, they got fucked.
In a similar turn inventory can be made redundant by ergonomics. Just by using the use key. Collect an item, then whenever you have to use it on the thing you have to use it on. Just press the use key. And everything will work out.
But this is rather worthless if you are providing puzzles for a player. As there is no active thought process to put the square block in the square hole. No instead, it's forget just press the Use key on the square hole and hope for the best. Kind of like sticking a fork in a socket, really.
My grief with coming to a conclusion is that I have realised I need some kind of inventory system. And I want to make it with as little UI as possible, while having the most ergonomic experience. Without compromising the idea that I would like the players to think about which items to use on a puzzle.
I look at old and modern examples and they are all near worthless. Inventory Grids, Button scrolling, Personal Stash in a static location, not pausing the game to look at your inventory (Hi Capcom!). And then from inventory grids we need descriptions and stories about items, and perhaps another level of interactivity like inspecting and merging with other items. It basically becomes a completely separate beast of it's own that sits slightly out of the game world.
It feels like every time you decide on something you burn a bridge behind you in this design. Either take another step forward, or start all over again.
Hence why inventory is dull. But I have thought about what I want. And it is now solved. Kthx.