Nahiri makes the equipment significantly stronger since you always have a creature to equip, and the tokens provide plenty of board presence to protect the planeswalker
Other Partner pairings, like Rograkh, Son of Rohgahh and Silas Renn, Seeker Adept, consistently put up strong results at competitive events
The Power 9 is a small set of cards that packs a powerful punch and comprise many of the most expensive Magic cards ever sold
Sure, Sanwell is not your typical mono-white artifacts commander
IIRC in Yugioh there is only a certain number of Blue-Eyes (from the show?), so you could put a rule on the card 'there may only be X Blue-Eyes on the battlefield at any time', Star Wars CCG used to have permanents that you could have 2 or 3 copies of in play, in addition to stuff you could only have 1 of, the concept would work fine here too, only this could care about both players' boards
Then, I can simply go to town with the deck