I can still boost lowbies in Utgarde keep with 1 ele shaman, in pve gear (flyingvasco, under my nick to the left). It's not as fast but still works pretty good for me. You obviously need to be creative with pulls, glyphs, totems and talents.

Hellfire ramparts is an instance i can clear way faster on my shaman than on my pally tank.

Anything below that is a breeze with magma totem, fire nova and thunderstorm.