Emily Short made an interesting post about different ways to make a fixed story moment fun in a choice-based game. Well worth a read!
I especially like the method of asking how the player deals with a situation, rather than if they do. There’s temptation to try to cover every possible choice a player might want, but sometimes it can be smoother to assume a certain level of buy-in (which needs to be earned, of course).
That article was a great read! I don’t know if I have anything substantial to add aside from agreeing that the if doesn’t matter so much as the how and the why choices, in my own opinion. IF (and traditional computer gaming) is limited by the fact that it is simply impossible to account for every single action a player may want to take. And if you give the player the option to opt out of entire plot points, you’ll quickly find you have no story left to tell.