adding a note to a model (free form text) might in fact be a nice
addition to the model editor. Obviously though, this won't be at the
level of individual model parameters.
It should appear at the top of the Model Overview panel in full lenght
on 2 or 3 lines because you need to discover the intent of the use case
when you enter it. Remember that if you have on average ten use cases
you need to click to and fro ten times to access the information.
If you hide the information still more deeply you will multiply
the clicking activity by two.
With panels the information is always very, very local, not synthetic at all.