Grist, The Hunger Tide: An extremely unique planeswalker that's also a tiny insect
You only need to gain life once or twice before its a very real threat on the board
With all of the Doubling Season effects in green and white this can seriously spiral
Regardless, I dont know that now is the time for more than 60 cards, but I do know that as the card pool expands, it gets easier and easier to find more spells of a similar power level, but no other lands are close to the power level of fetchlands, so the incentives to build to maximize the power of our lands over the power of our spells do increase in some way over time, which is to say that, even if its not right now, it could be someday, and getting there first might be the best way to truly break Modern.
There are no Floodborn in this deck, which is a bit odd for the Rise of the Floodborn expansion
Acererak the Archlich is a particularly fun example of what's possible with Dungeons