Weve gone for Reveka, Wizard Savant here, since its on-colour, and since it lets you burn your opponents out in a Mono-Blue deck, which is a rare thing indeed
And since it is both an ETB and Monstrous effect, Alpha Deathclaw can be looped to provide a consistent, devastating removal effect
With 31.5 rare in a box (with the other 4.5 rare slots going to mythics) you should open roughly eight rare planeswalkers per box, with four being the alt-art versions
Eight mana is extremely steep and many of the most powerful creatures in Magic are at the 7-mana range
Oracle of Mul Deya is a solid choice for the 6th best green commander card to have in your deck
Bontu's Monument helps this somewhat by discounting your black creatures by one mana (which most of your creatures are)