Reached 10 wins quite smoothly using Simic Mass Manipulation. This feels like the best deck in the format. You lose three cards: Hinterland Harbor, Llanowar Elves, and Entrancing Melody. Losing Hinterland Harbor sucks but you're a 2-color deck so your mana costs are relatively stable, and in the worst case scenario you could run Highland Lake. Losing Llanowar Elves is a blow but not too hard of one, because Growth Spiral works almost as well. Finally losing Entrancing Melody is painful, but not lethal. There's a healthy dose of planeswalker control in the format (undoubtedly since WAR has so many planeswalkers ...) against which Entrancing Melody is dead anyway, and you can orient the flex slots towards beating aggressive decks.

I used Chemister's Insight, Tamiyo, Frilled Mystic and Biogenic Ooze in the flex slots since I was encountering quite a lot of control. Ran into some white aggro decks as well that I generally defeated smoothly - they lost History of Benalia & Benalish Marshal after all. Conceivably a more balanced version of the deck could run something like Kefnet to hold the fort against aggressive decks, and the rest of the deck which functions unimpeded should pull through.

Aside from Simic I think the next best decks is probably Jeskai walkers, but it's easy to get run over by aggro then.

Yeah, losing Elves was the biggest hit, quite a difference between a t1 mana dork and a t2 one that does not ramp you into Threeferi - but there are plenty of cards to fill gaps. You could think about that 0/3 ape if you're still playing. That one could enable t2 Threeferi.

Dimir Control was rather oppressive - nothing you can steal and they just kill your hand. Also played Gruul but yeah, that felt weaker. Maybe add one or two copies of the white Finale to kill them.

I ran the same deck I used in Counters and it did amazing! Proliferate for the wins!

https://mtgazone.com/articles/gideons-s ... and-guide/

Azorius Prison: 3-2
Boros Mentor 2-3
Dimir Control 3-1
Golgari Midrange 3-1