Tier 1 talent:
Improves mana regeneration, which is one of the main Arthas problems.

Tier 2 talent:
Improves damage done by your E, which should be run on in each teamfight.

Tier 3 talent:
Heals and deal damage at the same time. Also, a good combo with .
situationally It seems to be good, when opponents team uses lot of stuns and you aren't lack of heal.

Tier 4 talent:
It's really your choice. is perfect crowd control, that allows your team make a strong attack (great combo with AOE and other burst spells). Army of Dead is good, when you are lack of heal.

Tier 5 talent:
It's really difficult one, so feel free to make an experiments. I prefer - slower attack means less damage taken.

Tier 6 talent:
Before it was useless. Greatly increases survivability in critical situations.
situationally Great burst damage. Better mana regeneration. A good off-tank choice.

Tier 7 talent:
All talnets here are greate. makes you super-star at the opening of bloody teamfights. is nice speed up, if you need to run away or finish off an fleeing enemy.