You need a Constitutional amendment to replace the EC, hence you need the states that are not NY, CA, and FL to ratify it. Good luck convincing all the non-coastal states to give up having any say in presidential elections.
You need three quarters of the states to ratify an amendment. States other than the population-center states benefit from the Electoral College. Those states can be expected to vote against repealing the EC and for efforts to improve it.
There are two ways to propose an amendment to the Constitution: two thirds of both houses of Congress or two thirds of the states, acting in a constitutional convention. There is one way of ratifying an amendment: three quarters of the states.
So, given that, I welcome the Democrats' proposal to improve the Constitution to better express the will of the people. We just need three quarters of the states to ensure any reform comes out right.