Thanks a lot for all your valuable input!
The first two Blackwell games suffered from this problem a lot, and is something you once complained about yourself, Andail. "Painful", I think you called it.
Ha ha, yeah I remember that
It was a clever little mystery, but it was painful because the protagonist could not express what you as a player had already realized, until she had combined the proper clues. It's one thing if you don't play an intellectual character, but when she's a detective you don't want to feel dumbed down.
The ambition expressed in this thread can be summarised to:
1. The player should not be able to advance the game without understanding it.
2. If the player understands the game, he shouldn't have to wait for the protagonist to catch up.
But I guess it's not really possible to provide a perfectly player-driven gameplay without implementing a) special tools, like the deduction board in Sherlock Holmes, b) some sort of text parser, or c) have all locations and objects turn into notes or memories (which can then be combined near-infinitely). Being a fan of simplistic controls, I'm not sure I'm in favour of either of those.
I even have hopes of releasing this on phones or pads in the future, and want a very simple GUI. Otherwise I was actually considering having a supporter character, like a Watson or something, with whom you could discuss the case as you progress. The discussion topics would be typed in via a text parser by the player, and "Watson" would ask you what kind of conclusion you would draw from certain facts and circumstances.
However, I'm scrapping parsers now, and also my game doesn't really have room for a side-kick...