It’s true that certain features, in certain situations, don’t work well when close to the center line with symmetry mode active. Generally speaking, if you want a feature to have no influence on the other side of the mesh, you would disable mirror symmetry. You can then work on one side of the mesh without concern for the other, and mirror the changes to the other side after you’re done working. This can be done with the Tool > Geometry> Modify Topology > Mirror and Weld feature.
Note that this feature only works in one direction, so in some situations you may first need to flip the mesh along the desired axis with Tool > Deformation > Mirror in order for the mesh to M&W along the axis in the correct direction.
Feature requests can be submitted to Pixologic via the Pixologic Support site.