Shadow King is pretty nice into Shuri and all the Bishops, Collectors and Angelas we're seeing right now. He should reset Kitty Pride when she's back as well. He also wrecks destroy decks with big Carnages and Venoms.
Polaris and Juggernaut help against Galactus. Killmonger wrecks Thanos and if you lose priority against Bounce, Zoo and Patriot/Ultron turn hold until turn 6 for maximum cube equity.
I tried Goose in the Domino slot here and it just feels bad not playing on turn 2 with this deck. A lot of games you're playing one card only on turns 3, 4, and 5.
Leech and Sandman are hard counters and you should retreat unless the board looks very favorable when those cards come out.
This deck's stats were better until Sinister London popped up, so I think it's a bit better than what you see here without that hot location. I had a 60% win rate with a .76 cube average over 60 games or so before.