Wrong.
The reason we take these talents actually help with survivability.
On a Pale Horse, allows extra movement, reducing all slows and roots placed on you. Meaning you are hard to peel from, and also you have the ability to get out of there quicker should the time come.
Desecration, allows for a whole group slow, those entering and trying to leave and slowed by 50%, meaning they cannot get away from you, but allowing you to keep on them, of again if the chance needed to out run them to avoid being killed.
Improved Strangulate isn't worth speccing that deep into the tree since you will most'y be able to lock out healers anyway with the 30% casting speed reduction from Necrotic Strike, keeping them from being able to juke sussessfully, so you can get off your Mind Freeze's correctly, locking them out from further healing. Also Death Grip acts as a ranged interrupt.