A shaman can drop a poison totem for the few areas where there are poison (really just gundrak and parts of draktharon), I don't think I've had to ever remove curse yet even though I have a mage and resto shaman. Its really just not a big deal imo, only in things like Naxx and other raid instances do curses and diseases and poisons matter a lot. Oh my tank is a pally so I can cleanse any poisons/magic off myself as necessary.