Stephen's Web ~ Managing the Complexity of Branching Scenarios ~ Stephen Downes
Stephen Downes comments in response to my post on managing the complexity of scenarios that merging paths makes it "more like a narration and less like a game." Is it bad for stories for learning and with specific learning objectives to be a bit more like a narration? Perhaps that's a feature, not a bug. Also, most video games do this to some extent. Mass Effect does not have 27 different endings, for example.
Twine (and similar systems) allow paths to merge, reducing the number of possibilities, but at the cost of making the scenario more like a narration and less like a game.