I think it's unfortunate that a scenario file contains several other scenarios. This leads to some ambiguities in the system, such as the meaning of a GivenScenario, and also in communication (is a scenario a collection or a scenario?).
It also is somewhat a violation of the literal meaning of scenario - which by definition contains other stories or scenes, not scenarios.
I think while the framework is still relatively young it would be worth addressing this design choice. Perhaps a scenario should contain stories, or something like that.
The main concern is removing the ambiguity about what a scenario is.