Would like to have a spline that is controled by vertexes (as shown on image), this are way easy to work with and produces a more "real" shape if designing objects like a hull, or wood furniture that may have curves that can only be build with what we call battens, which are "strips" of wood that bends to produce a curved shape, I have found on my expierence that this are the curves that are more true to the real thing.
I undesrtand we all want something that we use on our workflow but i truly believe splines controlled with vertexes provide a lot of flexibility.
Thanks