It's a good shape. The "sauce trough" thing is a little questionable though; having eaten a couple boxes, I think it would make more sense to have it on the inside surface, more sauce retained that way.
The series of podcast episodes is worth a listen. The task is not just imagining an ideal shape balancing the 3 constraints, but to do one that will actually come out a pasta extruder die. Getting the trough inside the curl might not work within that implicit 4th constraint.
IIRC, Dan's original design had an an internal channel, but the pasta die manufacturer said it wasn't feasible to manufacture, so the design was adapted into the trough.