I think SparBird is pretty bad as P2 and would expect that it would be destroyed by a competent P1 opening, but this is explicitly a resource for people’s first few games where no one is going to know what they’re doing, and P1 build vs P2 build would require doubling the amount of information and also include some discussion of tempo and value, and and and.
That said, just going Sparring Partner/Rambasa Twin as T1 is also a fine generic build. The only things I would explicitly stop new players from teching in their first few games is Boulder, Mythmaking, and most spells. Birds Nest is an exception because it’s a spell that gives you units, so it’s safe.
Yeah, I tend to think more in terms of “what should I keep” rather than “what should I worker.” It comes out to the same thing in the end. I would actually remove the discussion of Flagbearer, given the audience for the guide. They’ll realize what games Flagbearer can help with through play. Not worth the additional info.