Instead of taking away your opponents lore, you gain lore
Mufasa brings a few new tricks to the game and is the first card to exert, ready, or return cards in the inkwell
These decks serve as a good and inexpensive way for new players to try out the hobby
If youve made these changes and youre still feeling like your deck hasnt been powered down enough, some other options include introducing a new restriction (like a theme such as people sitting in chairs) or removing some particularly salt inducing cards (these are often stax effects like Winter Orb and mass land destruction effects like Armageddon)
Appa, Steadfast Guardian is a way to protect your board from a wrath, and thats the most common use case I can see for it
Being in Izzet colors makes it already more color restrictive, so unless youre playing exactly UR Murktide, youre looking at least into a 3 color shell to make Expressive Iteration work