Leaving the policy merits of the proposal aside, the Warren wealth tax is a brilliant tactical decision that could help her win the nomination. Why? Because it destroys any plausible rationale for a Bernie Sanders candidacy. Sanders already had issues with his age and his past associations; now he has been outflanked on the left by the wealth tax, which is a simpler, bolder measure than anything he has ever proposed. He can’t compete with it; he would be wise not to try.
Warren should have the fundi/class quadrant locked up at this point. She could still be defeated by a more charismatic candidate who emphasizes identity over class (probably Harris or Booker) or a realo candidate who calls for national unity against Trump and presents a more moderate, realistic agenda (Biden). Will that happen? At this point, I have no idea.