I would like to see the option to create a spline based on an edge loop, whether t-spline or mesh, similar to the create shape tool in 3ds Max. This can be useful for surface modeling and allows for concept iteration (e.g. based on lofted splines which follow a t-spline or mesh surface). This opens up more possibilities as the created splines do not have to be on a construction plane (as is the case with the current tools).
This feature should have options to choose between splines generated with CV's or control handles, the amount of CV's or handles in conjunction with smoothing options.