The deck is still a work in progress
It has been made to be a bit more defensive overall to buy more turns and burn opponent resources, the B/Y package is for defensively tapping things down and using the Aegis mana to buy more turns
Opening the gates of hell has been relegated to the sideboard as it's main deck usage is questionable, and in a lot of matchups it's best usage is charge phase.
I would not say the rest of the sideboard is totally optimal at all, you may want some amount of draw apes instead of Cooler but in testing it's good mana usage to draw 2 cards and put a body on board in the mid~ game