My 2 cents (or more like 10 bucks by the time I finished).
Been playing enhancement heavily since WoD pre-patch. Are they "viable"? Sort of. I'd say yes in certain situations.To give you an idea of what they do right now, on a geared enhance LL crits between 550 and 625. Everything else damage wise is weak. The dps isn't awful, but it is well behind rets, rogues, ferals, boomies, hunts, locks, and some others. Also, it's not bursty but rather consistent. Their heals are high at between 900 - 1000 non-crit depending how you gear, but you can only get 5 straight surges out before you oom and mana regen is slow. Their positives are still Wind Shear and Purge.
In certain situations enhance (and any shammy really) can be useful for taking out a priest shield or AGM instantly. Taking out a 1000 - 2000 shield is equivalent to some big damage. Granted, you're not always running into priests, but it is still useful to eliminate rejuvs, regrowths, mw monk stuff (whatever they're called), riptides, etc. In solo queuing 2v2 skirms, enhance can have a lot of success with a strong dps partner. Some of the biggest winning streaks I've had have been with a boomy or a feral. The damage is big and enhance makes it much more effective with keeping shields down and interrupting heals. Now if you don't get just the right comp though, you will lose a lot. You basically must have a high damage partner and you need to get someone down quickly or it won't be long until you oom. All in all though when I'm enhance, almost all of the time, people choose to re-queue together after that first match. I've had a few people get snarky and leave, but most of the time I've found people enjoy enhance as a partner. Now, ele has slightly better dps, weaker heals with much more mana, but with the constant 2 second casts for LB I've found the gameplay in arenas to be not nearly as fun or effective as enhance. You can of course play as resto and have great heals, purge, shear, and cleanse, but the damage is next to nothing. Enhance is a fun mix of things if you don't want to straight heal. Battlegrounds are a different story though. I think ele is still more effective there with Thunderstorm, and in battlegrounds you have more opportunities to keep your casting going to build up Fulmination burst.
In dueling lots of people since pre-patch, I was really surprised at how well enhance keeps up in 1v1 situations. Against ferals, if you can get through the first FB burst with heals, you can oftentimes (not always) get the feral on the run once they get to to around 30% health, purge their rejuvs, and finish them off. BM monks are fun fights, you just have to heal and wear them down and be ready to Ghost Wolf when they run for LoS to heal, to hopefully get a shear in to interrupt heals. Rogue fights depend on you faking the kick basically. LoS hunters, heal, and get shots in when you can. Locks are a fun mix of interrupting, running, healing, etc. Priest fights are really fun, take a long time, but generally enhance ooms. Good WWs and Rets are still a loss I'd say, but most classes have a rough time with them.
Anyway, viable? It depends really. Fun? Absolutely! Since pre-patch I've played a bit of disc priest, ret, boomy, and resto sham, and I have the most fun on enhance by far, even with putting out weaker damage and oom-ing much of the time.
