I personally leveled all the way to 60 as a Ele/resto shammy. The instant cast shocks were some of my favorite spells in the game and the resto helped keep mana costs down. I never liked the enhancement tree that much because I felt that If I wanted to be a warrior I should've rolled a warrior. There is also a TON of luck involved in Wind Fury. As Madson has respec'd recently I've been playing him as an enhancement shammy. Some battles are over amazingly quick when WF procs, but others are near death experiences.
Of course I spent 60 levels getting elemental gear and then switched to enhancement, so maybe with the right gear it would work better.
I still stand by the Elemental Tree. You are basically a insta nuke caster with decent melee abilities. I used WF weapon mostly and when it procs it's nice, but not necessary.
When I leveled I did so through this
Elemental Tree
1st Convection / Concussion (10 points) ( cheaper & Stronger Shocks + Openers)
2nd Elemental Focus (1 point) (10% chance for free next spell, feels like it happens all the time, LOVE this ability)
3rd Reverberation (5 points) Faster Shocks
4th Elemental devistation / Call of Thunder ( 5 total points )Elemental Devistation is new, but considering you are almost always within striking distance when you are shocking opponents this could be nice. When i leveled I put all 5 into CoT. I have to admit, other than the Lightning Opener and the occasional AB Chain Lightning I found it to be somewhat unused, so the Elemental devistation might be a good trade off.
5th Elemental Fury (1 point) When you crit, it's 200% the original dam rather than 150%, this is a no brainer.
From there I am a lot less adamant about my decisions. You could continue to buff your lightning damage so you can get to Elemental mastery (100%Crit chance) but it has a beefy 3 minute cool down so I didn't use it as much as I should have. Looking back at a lot of the new stuff on the tree since I left 6 months ago it might be worth it so you can chain together all of the other abilities that proc on a offensive spell crit.
In the enhancement tree, I think Imp Ghost Wolf might be great under level 40 but I rarely ran from fights, and it only works outdoors so... meh. Soneclaw totems let me get away if I really needed to run. I was never impressed with 2h weapons and I liked the bonuses to Armor and Int from caster shields. With that said, at 60 my mana pool is somewhere around 3.5 - 4.5k, so the ancestral knowledge is a waste as it only grants about 200 extra mana after 5 talents.
Speaking of efficiency, Lit Shield is your most efficient offensive spell, the talents make it even more so. I suggest this talent if you spec enhancement. Just don't forget to keep it on in the longer fights.
The Resto tree is better in my opinion because of the increased survivability and mana efficency it offers. Reducing your fastest heal cast time and mana cost through Imp healing wave and Tidal focus in extremely valuable. This also leads to Totemic Focus which makes your totems more efficient. Healing focus is nice as well for soloing as you'll need to heal as you are getting wailed on. Tidal mastery can also be a nice addition to your lightning offensive spells. With Natures swiftness (>10 sec cast becomes instant) your lightning spells become much more useful in battle as well.
Well there are some of my thoughts. Just thought I'd share a different view. Hope this helps. Of course I didn't cover all the talents but I thought I hit the most important ones. Tell me what you think.
The build that I think I'd go with is
here. It's a 31/8/22. From first glance the best talents in the tree seem a bit too expensive for what they do. Either that or they are too focused on groups, which I'm not interested in.