I'm not so sure. Unless you outlevel or outgear dungeons significantly some of the mobs hit pretty hard.

Even with a paladin or druid while you're gearing up the mobs in all of the 55+ dungeons can drop your health super fast. Without the extra block value, parry and armor from the enhance tree you'll have a rough time. There's no way you'd be able to 5man DM:N or UBRS as an all shaman group with no CC.