Hi Kasper and Leo,
I'd also like to make a contribution.
As a physicist, from my point of view I think that
a tutorial on voice 1. would be an excellent way to combine the experience of using the Cadabra manipulator with the opportunity to discover/learn the basic programming logics (seeing their direct projected application in the context of physics). Thanks to its Open Source nature, Cadabra is predisposed to be a valid tool also from this point of view.
for the other points, I am convinced that the extension of the code/examples provided to the user in a wide range of fields is always a good thing (the user can learn/use/modify according to the specific interests -> new extensions/ideas for the future).
I am therefore in favor of all the points, specific or less than they are :)
Thanks and regards,