I think it might be helpful to add an option to Segment Editor to disable smoothing of the surface when generating it from the label map representation. When regions are small, smoothing can lead to significant under-estimation of the boundary, as shown in the screenshot below.
Of note, the option to disable smoothing was available in the legacy editor.
The segmentation dataset used in this example is publicly available in the TCIA QIN-HEADNECK collection, and can be downloaded using the TCIABrowser extension. You will need to install Quantitative Reporting extension first to be able to load DICOM SEG series. The details on patient/study/series are shown below.