The focus on Challenges was maintained, but now more consistent and with a more aggressive character curve, which allows positive trades - that is, lower cost characters trading with the opponent's larger characters
In case Arcades is removed, his Commander deck has cards like Assault Formation to keep the defenders online, and the deck can even "flicker" its defenders so ETB effects like Arcades' own can be used all over again
Primarinas Fairy typing adds a strategic layer to its role in battles, enhancing its versatility and appeal among players
Unfortunately, this realm was discarded because Mai Tais aren't fantasy enough
Whenever Unesh or another Sphinx enters the battlefield under your control, you reveal the top four cards of your library, an opponent splits them into two piles, and you put one pile into your hand and the other into your graveyard
Here's how the deck looks with the upgrades added: Also to pre-emptively address some comments: one direction that you can take the upgrades is to really lean into Sliver Gravemother's encore ability and turn the deck into a straight-up Encore deck -- Buried Alive and Entomb cards to put slivers into your graveyard, Convergence of Dominion and Zirda, the Dawnwaker to make encore cost less (though PSA Training Grounds doesn't work, I see people suggesting it but sorry no), Mondrak, Glory Dominus to double the encore tokens, Sundial of the Infinite to keep the encore tokens permanently -- that sounds sweet and all but you'd need to do a massive rework of this entire precon, turning it from a Go Wide Sliver Combat deck to Sliver Reanimator essentially