I think that optionality is more meaningful if options aren't explicitly stated. I want to be thrown in the game and be allowed to "discover" options.
This is done well in games which focus on spatial navigation (Demon's Souls comes to mind), but it's poorly done in games that focus on conversations. Visual novels, CYOA's and RPG's are all having explicit options.
Games with text input, such as IF's and the very first Leisure Suit Larry, are close to achieving this but are unfortunately suffering from the consequences of subpar Natural Language Understanding algorithms. Players should not fight with poor NLU and they should not bang their head against the wall in order to make the slightest progress in the game.
I think that very few options should be explicit and that majority should be implicit. Now, I'm making difference between implicit and secret options and I'll use Demon's Souls to illustrate that difference:
Secret option: Executioner Miralda
Implicit option: Lord Rydell, a prisoner in Tower of Latria, who is heard yelling "Please help me" while you play the game, hinting on his presence
The difference lies in that there is no hint for the secret option, whereas there is one or few very subtle or even subliminal hints for the implicit option. In Demon's Souls, If you decided to look for side-quests, you'd recall Lord Rydell immediately, because he was seeded to your subconscious mind through constant yelling.
The same concept, I believe, can be applied to dialogs, where text subtly hints on or even subliminally seeds options to your mind which later feel like your own discoveries (but it's really only exploiting your biases).
This could work with rich combinational style of interaction without making players try random combinations because they don't have idea what to do next. A combinational style of interaction is the one where you combine information with context, such as that one found in Ace Attorney styles.
Doodle God too is an example of combinational interaction where you combine information with information to get new information.
Derren Brown, thus, should start making games.