You'll be able to indiscriminately dish out damage thanks to inclusions like Persistent Constrictor and Harsh Mentor
When your opponent does play a powerful creature, use a removal or counter spell to get it into their graveyard and boom, pay a paltry amount of mana and that puppy rises again, but this time on your side as an unholy abomination of itself
The extent to which or way in which recurring a card is more powerful than tutoring for a card is often overlooked, but its really highlighted with Mystic Sanctuary, because it allows you to cast the same spell several times even if you only have a single copy in your deck
Plus, apart from being tribal Wizards, Mairsil, the Pretender is a great build-around-me commander that can go a bunch of different directions, and Kess, Dissident Mage opens the door for a sweet Grixis spellslinger build
The first version we tried used 2/2 Bird tokens with a landfall ability that gave +1/+0 until end of turn