On the other hand, it might be better to leave that to the user, so that he is able to have a figure exactly the way he wants. In this case, maybe we can provide helpers to make that easier.
2) A similar representation might be used for the other metrics using different axis.
This issue actually covers three questions, and should probably be split, if we follow more than one of them.
1) It might be nice to have a graphic representation of the Fry readability formula.
https://en.wikipedia.org/wiki/Fry_readability_formula
On the other hand, it might be better to leave that to the user, so that he is able to have a figure exactly the way he wants. In this case, maybe we can provide helpers to make that easier.
2) A similar representation might be used for the other metrics using different axis.