[DrKvothe]

At higher levels, you're an essential part of any 6 man group. Mobs scale very differently than players; at your level, the difference isn't too large, but at upper levels the mobs are distinctly tougher than us. With expert crowd control, you'll be fighting 1 at a time most of the time, but even then don't expect fights to be easy without slow. With slow, however, mob damage is reduced to 25 or 30% its normal level; your spell is effectively doing 70-75% of the tanking.

Honestly, that would be enough to make us an essential component of a group. Yes, enchanters can do that too, but if an enchanter is doing CC, haste/clarity buffs, and slows, forget about charming. And enchanter charms are a huge part of your group's dps. So another way to look at it is that by being there to slow, you allow the enchanter to charm. With your malo line of spells, you also greatly reduce the chance of shit going badly when the enchanter charms. This is the second important role of a shaman in groups, and it will be greatly appreciated. When your enchanter dies, it's often a wipe.

Your stat buffs are over-rated. I'm skeptical that they ever really make a difference in 6-man content. However, there's a powerful psychological effect; when melee dps chars have maxed stats, they feel better about their abilities even if you can't tell the difference. The exception to these statements is your regen line of spells, which act as a super mana-efficient heal. These reduce the frequency with which a cleric needs to CH your tank, and are particularly useful for monks while they're splitting, since they'll be regaining quite a bit of HP while they lie around =D.

Your root line of spells is also incredibly useful in groups. Rooting adds isn't always necessary or even a good idea, but in some cases it can be very helpful. Since your roots dont do damage, the enchanter can mez on top of them, and then when mez breaks the mob won't be able to run over and slaughter the enchanter. Yes, other classes can root, but at the times when root is most useful all the other classes are going to be busy.