You've got it backwards. Newtonian theory does not rule out perfect spheres (or any other mathematically perfect shape), hence the possibility of non-determinism.
It also better rule out general fractals as well, cause some shit will happen between these as well. Not fully sure, but it feels like Newtonian doesn’t really work with anything non-finitely jagged, cause geometry has extremums or simply insane behavior at everything non-linear non-finite.