If you use ray of frost for 11 AP per cast instead of another channel skill, you dont need anything for cost reduction and you can use aquilla cuirras in your cube for extra defence with 100% uptime. The channel skill doesnt do significant damage anyway, so if your current one does more dmg, that does not matter.

Now your build is starting to look too defensive already, so if you do that, and i advise you to do so, you can take away other defensive measures like that travelers pledge and choose more offensive things.

I also disagree with those rubies in armor. That might be a good idea when you have 30k int from paragon, but its not a good idea for newer low paragon players.