Q u o t e:
The purpose of dual spec was not to make talent choices irrelevant (because you'd only have a talent in the cases where it was most useful).
The purpose of dual spec was to make it less painful in those situations where you often switched between two commonly-used specs. This is the reason we placed so much emphasis on remembering action bars and less emphasis on the gold-saving aspect of the respec.
You won't see more than two specs for a long time, if ever. Let's see how the first one plays out for more than 6 weeks first.
Duel spec's are amazing. However one of two things need to happen.
Healers be given an extra spec.
OR
Healers be made to scale as well with gear as other classes. Made to be powerful outside of a raid.
Let me explain what I'm talking about here. I've been pretty dedicated in doing the argent daily's recently on my Priest which I do with my Girlfriends mage. I've been also doing them on my Protection warrior alt.
On my Priest. Trying to kill 15 Scourge without help is horribly miserable. On my Priest it takes roughly 20-30 seconds to kill a single scourge and uses about a quarter of my mana. Now in BC it still took that long to kill something, but I would always finish a fight at nearly 100% mana (Yes, My regen was that good).
My girlfriend's Mage can literally one shot these things (and never takes more than 2-3 hits to kill them (under 6.5 seconds). Her same mage can also AoE Down 10-15... Killing them in a matter of seconds (Although at the risk of dying a swift death if not done properly).
My Protection warrior can round up 30 of these things and AoE them down in around 45 seconds and come out with full health (using Shield wall, Last Stand+Regen). Of these same 3. The Protection Warrior is the only one that can also solo "Threat From above".
Now all 3 of these Toons are geared very well. Each in iLvl 213 gear or greater (With the warrior being the least geared (with about half crafted epics). Of these 3 classes (DPS, Tank, Healer). Only the healer has issues doing anything outside of a raid. The healer is the only class that IS NOT POWERFUL on his own. The Healer is the only class that doesn't get much much more powerful with gear in a solo situation. The Healer is the only class that relies on a group to get things done.
Now as I said. Two solutions exist. Give healers another spec so they can use their DPS spec along with their raid/PvP spec. Or make Healers good... Just like you've done with DPS and Tanks.
See the problem is... People who are primarily a DPS in raids don't need a spec to do their job inside a raid and then solo doing daily's because their raid spec covers both. Tanks who have a raid spec can also very successfully do daily's and solo content on their own. The only raider that does not do solo content well on their own is the healer. Healers have bad damage output. They have low survivability and the spirit based healers also have terrible mana regen on their own.
Just some food for thought before you toss away the people who dedicate their wow time to following people around and keeping them alive :D