If your model domain has only local discontinuities, you may use partially unstructured meshes. Re-mesh only parts of the domain which are characterized by discontinuities. If other spatial parts of the model domain have a layered geometry, then there is no need to re-mesh it. If you keep 3D prismatic elements for layered based geometries you still have the possibility to work within the Slice View.
Of course, other geometrical settings of the mesh may have a different convergence behavior of the equation solver. As always, you need to assure a mesh with a good quality. Some quantitative indicators are provided within the Auxiliary Data section of the Data Panel.