The only fair way to do it would be to have a constitutional amendment allocating electoral votes by congressional district winners plus two for the statewide winner rather than cherry pick a few states.
As a constitutional lawyer, what do you think of the constitutionality of state referenda passing such a proposal rather than the state legislature? I don't think a referendum satisfies the US Constitution's requirement that the state legislature determine the method by which a state's electors are chosen.
Since each legislature passes ordinary laws to establish its election laws, in the 25 (?) states that have the initiative such as California, this can also be accomplished this way.
Congressman Billybob