I love it how you made a fine example for this system, I would love it doing dps with this system, seeying the current one makes me feel like a mage...
Even though I would like it to see this system on live, I think there would be to much QQ about it.
For 1, there wont be a perfect rotation anymore. People have to figure out a new rotation to do nice DPS, and they just dont want that kind of stuff.
Second, This means Blizzard has to make a soulshard Attack to regen health (Could be HoT like), but also something in reverse (Sacrifice HP to gain a shard).
Third, All attacks have to change. No more mana means that every attack needs to be remade into a "propper" health system.
Also to those saying attacks that large AE attacks from bosses would leave the locks alone, remember that we would use Health instead of mana. Our health would go down every single attack we use, so there is a good chance we would die in the same attacks. The thing that would be lame though, is that we might need more healers in the raid assigned to the warlocks...
I personally would love a system like this, it just seems like something that needs way to much more work for Blizzard to do...