You can still burn or counter anything you need to to stay alive in the early game, and then once Niv-Mizzet, VisionaryNiv-Mizzet, Visionary comes down, the burn spell you have left over is a draw spell
The reason for this is that +1/+1 counters require counting and having a singular number for both power and toughness (much like the +1/+1 counter itself) makes the math easier
Reforge the Soul $6.96 Miracle is a tricky mechanic, and Reforge the Soul is the Wheel of Fortune of that mechanic
Imagine sacking Clues, Treasure, or other tokens just to fuel the Marvel and gamble for haymakers, waiting for one spin to completely turn the tide of the game
The Theros gods are always creatures on the stack, regardless of your devotion, so Negate wont work there
How many card draw effects win too