Brewing takes time, research, buying, building, and testing
It will also be focused on designing cards that could likely be printed on cards by Wizards of the Coast, and most likely in a standard set (planeswalker deck planeswalkers are balanced completely differently, and supplementary set ones are also separate from that) but card creation is still a creative act and, in the end, youre the only judge of what you can or cannot do on a card
This gives you more value in the form of Squid tokens with islandwalk once it dies
Mirrorpool can also copy instants, sorceries and creatures we control by sacrificing and paying some mana, which is also great in Eldrazi Tribal where he have many high cost, high reward cards
Then most of your creatures are tapping naturally
Bake Into a Pie gives you a solid removal spell that leaves some Food behind