On PVP, ANY DPS class is squishy and Sorc is part of those DPS classes but being squishy is a big big problem for Sorc because how can you provide good crowd control (Nightmare Totem) if just getting near to enemies would spell death? The answer is obviously become tanky enough to close-in and make enemies sleep towards their death. This is also a good for countering Bards hiding behind since they won't be able to provide heals for 6s unless they were attacked and woke up.