It has occurred to me that the thinking process of making a spline is very much like sculpting. In college we did quite a few models in a wide variety of mediums. One medium that we used quite often, that I didn't care for so much but then grew to love, was plaster. Plain ole plaster of Paris that we would sit a carve, shape, and examine for hours. Starting out with and paper, about 160 grit and working out way down to 200 and meshed as well to help create the form. Getting the "final" shape to take shape became the end result of your "design eye" and how you understood the form. In the end what you were suppose to learn was that it is not so much about the individual "point" but the whole model in and of itself that mattered.
Translate this to the creation of splines. We use points placed along a spline to help control tangencies and curvature continuity into other surfaces. Imagine if there were a tool that you could use to manually "smooth" out Splines. Imagine if the cursor, once you activate the tool, would become like a small circle (or a circle of any size for that matter, indicated by you in the property manager) You could then take that circle and run it along the spline, somehow pushing it... not so much out of place that it distorts it, though this could be an option in the property manager that you could adjust, but a way to sculpt it so that the curvature would be much more manageable.
The whole idea of using points to control splines, though valid, still address the "little guy" when it is the entire thing that we want control over. Not in every case would this apply, but I think just having the ability to have a global control tool not just on a spline at the sketch level, but then start to take it a step further for surfaces.
Imagine if you had a tool that once you had two surfaces touching, instead of having to go into the sketch level and not see the surface that comes after, because of history and/or relationships. If there were an accurate way to sculpt between two to more surfaces that would be able to create curvature tangency/curvature continuous geometry.
As an ID major in school, form, astethitecs, and dynamics of how all of that played out is and should be a key integration into the 3D world of CAD. The program is parametric and any changes that are made at the surface level should translate into the underlying sketch of that surface.