That's an excellent idea, Valery!
I like tools with similar functions to be consistent in their usage. The complex profile tool already has the feature of being able to adjust both the pen and linetype for each edge (as well as the material), so it would be natural to have the same sort of interface to adjust any polygonal based object.
This should really be extended to polylines also. It would be great to keep a polyline as one object, but have the ability to set different pens and linetypes per edge. (Or even hide an edge completely, but still keep it connected.)
Essential!