I strongly doubt either party would like it if a state's EVs are split between candidates. Democrats would never want California's, or New York's, or Illinois's EVs split. Republicans would feel the same if Texas', Florida's, or Ohio's EVs were divided up. But the fact remains that the EC is an obsolete relic of 18th century thinking, and is totally unfit for the modern world. It makes geography, i.e., states, more important that people. And the idiotic winner-take-all arrangement in effect disenfranchises all those who voted for the candidate(s) winning fewer popular votes.
The EC cannot be salvaged. I'm going a bit off-topic--but not only should the President be elected by direct popular vote, but the candidates running in the November election should also be chosen by the voters in a nationwide presidential primary. Political parties can nominate someone, but the final decision on who runs is up to the voters. I'm sure none of this will occur in my lifetime. But I predict that before this century has ended, the Constitution will be amended. The EC will go the way of the Articles of Confederation. And good riddance.