how are you going to kill?
Why a cleric if you run obelisk?
The Unicorn is proabably to expensive to pay upkeep for. I am in total not so found of it, take a KoW instead.
Bindingflash and Pillar of Light are kind of meh, maybe consider a dazzle (and of course once PvS)
I would double the dawnbreaker ring and the hawkeye, as this is one of the only ways to really ditch out damage.
Why run an Ironvine if you have the unicorn (ok that will be gone), but I rather use a regrowth belt in such a deck and boots. (or even vet belt+regrowth if you play slow mana denial) Maybe second chest piece
purify, more dispel, more dissolve, (or harshforge monolith if you want to go with mana theme). I'd take a nullify instead of the second armor ward. Devine Intervention is always good to have, can work as a nullify if needed for a crucial dissolve for example ... or a teleport...
Arcane wards?
Who gets the agility?