Thanks for the input! The reason I don't take destruction is that even with the added damage, you won't be able to take out anyone by yourself. And if you have help from an ally, they will be able to finish off the target even without your added damage.

On the otherhand, the extra mana that frozen waste gives allow you to play as a semi specialist.
Whenever you finish a typical length team fight, you will have around 30-50 % mana left with frozen waste. From there, you can just grab a drink at the healing fountain and you can immediately go clear minions in lanes, which frozen tempest does really well. Doing this will allow you to get more globes for regen master. Or, you can go and start a camp (which also give globes) while your teammates hearthstone. In infernal shrines and battlefield of eternity, you can take a siege camp by yourself at the speed that sonya can (with biting cold at level 13).

With frozen waste, you don't have to hearthstone back very often. Without it, you'll run out of mana after each team fight.

Also, team fights won't always be 5v5s. You'll have a lot of random semi-teamfights that happen across the map. With frozen waste, you don't need to worry about only using frozen tempest for crucial fights.

Thanks, I certainly hope he becomes more popular at high echelons of play.

Hey, I'm glad you found it helpful. This guide is still a work in progress. I'll be updating it in the coming few weeks or so. Good luck mastering arthas.