Rather than feeding off the players’ enthusiasm, in my experience, they feed off mine.

On the topic of reacting to crises vs pursuing agendas – to that end, I find that involving the players in creation of the crises/fronts/etc helps make these actions similar. By reacting to a crisis they created, they are pursuing something they wanted.

Aside to your aside: I really like the author vs actor delineation, but I personally use the divide of setting heavy vs setting light – where “story games” tend to fall on the light end of the spectrum (setting created during play) and “trad games” on the heavy end (setting in a number of books). I wonder how these two ideas would work on a 2D plot…