Looking through more Ixalan spoilers, I feel that the Jace/Anointed Procession could fit in a Pirate Tempo Deck. The following are the first set of updates I made:
Removed
4x Slither blade
4x Glimmer of Genius
2x Regal Caracal
2x Censor
2 Irrigated Farmland
1 Island
1 Plains
Added
4x Siren Stormtamer (Not yet registered in Tappedout, Ixalan)
4x Dreamcaller Siren
2x Angel of Invention
2x Aether Meltdown
4x Aether Hub
Reasoning
Siren Stormtamer just provides better value than slither blade, and it fits the theme of what we are trying to do better.
Card advantage is nice, but I do believe supreme will is enough for this deck. I recalled when I played U/W flash back in Kaladesh standard that Anticipate and clues from Thraben inspector was the only card draw the deck had and it functioned great. Therefore, I cut Glimmer and added Dreamcaller Siren. Siren fits our tempo plan, and gets us flexibility with flash. With the current list, there is a good possibility we will have at least 1 pirate on the board to get the tap down trigger.
Angel of Invention seems to fit better here provided a buff to our entire board, and still can help us go wide. I am also contemplating Djura, With Eyes Open as the 5 drop. He will be able to tudor up Jace, but not sure if he truly fits. The 5 drop spot still is up in the air at this point.
Finally the addition of Aether Meltdown and Aether Hub, I believe just solidifies the deck. It needed more removal (still might need more), and I didn't like the mana base. I believe Aether Hub helps here, and with Aether Meltdown we can produce some additional energy to full the Hub.
That is all for now. I appreciate any feedback you have for this deck. Thanks!