"""""""""" that uses what is called a constraint-based curve modification system, to modify the control points in such a way to change the point that the curve is going through at one spot on it.
In MoI it's basically a mechanism for manipulating a few nearby control points all in one drag operation rather than dragging on points one at a time.""""""""""""

I reviewed the thread in the link you posted and see the poor results, but that is a bit different than what I was envisioning.

I did a bit more thinking about this, and the UI impact.. Let me illustrate, although, this will depend on the "constraint-based curve modification system" MoI uses and how hard coded it is and access to it.

This will get into the "rebuilding the curve to get the results" I had mentioned (But not really rebuilding the curve....)

So Here is a curve with points that i may want to edit:



If I rebuild it, I can get the action I want, with MoI's current point editing structure and control the degree by the point density:





I suppose it really comes down to a question of "Is the mechanism for manipulating a few nearby control points" located in the Show points command or hard coded?

If it's in the command, we could use some logic to have the command "Think" the curve had however many points were in a "Soft selection" numerical input box (Whatever the number typed in is equivelent to scope desired) and a "show points2" command could be made with this single added input field... This gives the "rebuilding of the curve to get the results" option, interactivity.

Of course if it's hard coded in the program logic, then this is not relevent discussion... :o

I must be nuts!!!!