Being mono blue it might be better running
Secrets of the Golden City over
Divination, with all the artifact setup there is a good chance to have ascend.
Maybe consider dropping
Aetherflux Reservoir, with 4
Trophy Mage you should have plenty of ways to tutor up a
Bontu's Monument.
I feel
Blink of an Eye would fit well in this deck, able to cast it for 2 or 4 it fits nicely with all of the three drops.
Being able to target all non land permanents also makes it more versatile and even able to save one of your artifacts in a pinch.
I would suggest some copies of
Negate in the sideboard for control matchups.
Some other considerations:
Naban, Dean of Iteration - works well with
Trophy Mage and
Naru Meha, Master Wizard.
Bontu's Monument triggers twice for some more life gain. Also works well with the
unsummon effects you have.
Glint-Nest Crane - assuming 16 artifacts in the deck gives it around 72% chance of success.