From what I understand (and what I'm going for on my shaman once he's leveled) as ele/resto you can stack spell penetration and use downranked lightning spells until you get focused casting, then unload a full powered lightning bolt/chain lightning for free. Damage is spikey and generally sub-par, but you can do some decent AoE damage and keep your mana pool relatively high while also providing buffs and emergency off heals. Penetration gear is also pretty trash for other classes because of warlock curses, so you'll usually have a good chance to get it on the cheap or not have to compete for it. You're gonna look like a clown, you'll be sub optimal dps most of the time, and people might mock you, but you'll find mana easier to manage and be a decent addition to most 5 man groups if they let you do your thing. Good luck finding a pve group that'll let you play ele though, raiding will be difficult to justify without mana tide. :p