Hey there,
I've been experimenting with a Dawnbreaker book recently. Hope I can give some useful opinions!
I would suggest running a harmonize if you run a TOA. I've been finding my games with monks are not always spent gaining mana.
Asyran Cleric ---> I've been loving this creature. You can meditate anywhere in the arena and gain mana. He can heal your mage when they try to focus your mage down, and if they rush early they are ok at defending for low mana cost. Since you're using a priest, I suggest making it your Avenger if you think you won't have time to get the unicorn out. On a side note if you make it your Avenger and they go after to kill it, the Cleric usually pays for itself and you can gain an advantage. Personally I prefer Asyran Defenders as my Avenger.
I was wondering if you prefer Mana Flower over Mana Crystal. Personally I prefer the Crystal because it feels like it can take more damage in the long run.
Battle Forge ---> I'm not sure if you're going to have enough mana to support this. If you want to put it in I would suggest adding a Meditation Amulet. If you do use both your TOA and Battle Forge I don't think you will find time to cast the TOD. Mana is really tricky for Holy Mages to work with. If you are only using your TOA once every two rounds (Maybe cutting back after 4-5 cretaures)---> I don't think you should cast it in the first place.
Valshalla ---> While I love this card, I often find I don't have time to cast it or the game is over by the time it would trigger it's ability. I'm curious if you have games where you got full use out of it. The Stun/Daze chance is really nice though.
Love the Armor Ward with Nullify
I think you should add in a Dawnbreaker ring and take out Ring of Asyra. Dawnbreaker combos with both your melee and any holy attack spells you cast ----> Sunfire Burst is awesome with it. I don't think you're going to cast enough holy things to make the Ring of Asyra worth it, but the extra damage can stack nicely.
Personally I don't think you need the Battle Forge. I think you can take out the Leather boots and Gloves and replace it with a Rhino Hide for the same cost. If you need to armor up early it is very simple too. This also means you can have high armor and Gauntlets of Strength and Reflex Boots for those really late game buffs. I would suggest using a Regrowth Belt though instead of Leather Belt. The passive healing is amazing.
You should consider Wand of Healing. Since you are not a Priestess you need a way to remove stuns/rots etc. I know you have a purify, but Gorgan Archers can ruin your day without Healing Wand. They are also great for cheap healing at action inefficiency for when you just need to survive while your creatures kill the enemy.
Just kind of rambled here, hope you can find something interesting in this