Currently, the ! _RebuildUV command is limited to the following types of approximation: Normal, Loose, Tight, StraightSections, Uniform.
I propose to add another type called “Adaptive”, which should take into consideration the input geometry and create a new surface whose control points are more dense around smaller radii, and fewer around control points around the less curved areas.
Something similar is achieved by the “Adaptice quad count” option of the ! _QuadRemesh tool.