Surely the amount of certainty students want to be left with depends on the type of text they are engaged with? Yes, with an airline announcement they want to be 100% certain which gate to go to, but they might not need to be 100% certain there was a ‘please’ before the ‘go to gate…’
And all those cackling Spaniards surely don’t understand any Almodovar film with zero uncertainty. The most important point I think you’re making is we need to be super clear why we are asking our students to listen to any text in the classroom (and the fact it’s on the next page of the course book is no justification at all) and then try our best to help them understand in a ‘real’ way – i.e. as closely as possible to the way they’d want to understand it in the ‘real’ world. A high percentage of task authenticity is the aim, not zero uncertainty.
So please do improve the listening sequence, but first of all by considering if listening to the gnome interview will motivate the students at all and then by deciding how would they engage with the text authentically. If text transcription helps them to develop their ability to do this then all well and good.
You write: “Surely the amount of certainty students want to be left with depends on the type of text they are engaged with?” Yes, that’s true to a certain extent. But I also think that – in the long run – the amount of certainty that the learners want to be left with should depend on them. If, for example, you and I are listening to the same (global) weather report, and you live in Argentina while I live in Spain, we will each have different needs, and hence different questions that we will want answered. And hence we will be listening more or less intensively to different parts of the text.
In the end, no coursebook task is going to satisfactorily predict the degree of certainty learners will need, nor the degree of uncertainty they will tolerate. It might be better if they didn’t include tasks at all, but just directed the teacher to ‘mediate the text to the extent that seems necessary’.