I cleared naxx25 last night on my resto shaman and the #2 and #3 dps spots were both elemental shamans on a number of fights, including Maexxna, Sapphiron, and KelThuzad (played by non multiboxers, and they had really good gear). So imo they have gone from usually-last to very-competitive.

Of course on my mage (my main in a guild) its usually a geared warrior/DK, followed by mages/hunters, followed by ele shaman/boomkins, so it really depends on the gear level and skill level of the players now more than the class.