I lvl'd elemental until 65 then switched to resto. When Wrath came out, I stayed resto for about 3 lvl's then switched back to elemental. As resto for those 3 lvl's, it took forever to kill anything, although, they couldn't kill me either. When I switched back to elemental, I was still using all my BC gear, which I didn't replace my 1st piece until lvl 78.
One thing I noticed though in Wrath is that it seemed that most of the quest rewards and drops in instances where geared toward enh. Now, I don't know if the instance drops are slanted that way or if I just had bad luck but that was what I was seeing. As I got higher into lvls, I started seeing more resto/ele gear drop and from quests.
I lvld my shaman with another shaman who was enh. I can say that when it came to dps, we were about even until lvl 60 or so. At that point he pulled away in burst dmg but on ling fights, I caught up.
It mainly comes down to, do you like casters more or melee? Either spec is a great spec to lvl. Staying resto though will make you tear your hair out until you are rdy to do higher instances. Just remember, you don't always have to have mail armor. Leather, and even some cloth, is still good to wear as a shaman until something better comes along.
On another note, looking at my spec, I realized a small mistake in the talent pts. I forgot to take the pt out of Imp Reinc, that was left over from lvling.
As for not having anything in healing grace to reduce healing threat, I am undecided on that one. I have been watching Omen alot on some of the instance fights in 5, 10 and 25 man runs and I still creep up there pretty quick. Chain heal generates a ton of threat. I have noticed a few times when I am 2nd on threat and have to make sure I try and back down just in case the mob decides the taste of the tank is not very satisfying and wants something a bit squishier yet still crunchy. Now, that is usually only happening in 10 and 25 man runs. 5 mans I am pretty much single target healing.
That being said, the only time I have found healing focus to be of any use is in PvP whne a horde is beating on me. Other than the times listed above, I am usually not getting beat on and if I am, well, something has gone terribly wrong and we prob won't survive anyway.
Anyway, looks like I need to fix my spec just a tad and correct the remnants of elemental that are left over. I shall now end my wall of text.
PS - Yes, the elemental weapons talent is nice and earthliving weapon is still good IMO.