Every state has a voice as it is right now. If we changed to a PV setup, people would only campaign in places like CA, NY, TX and FL in order to drive up turnout. Many states would be neglected.
Lets see, right now all the action is in about 5 or 6 states. So that's not a valid argument. Also, the large states send more tax revenues to the federal government, yet when it comes to the national election they are virtually ignored, thereby depressing turnout in these states.
Maybe when Democrats have a lock on Florida and Texas becomes a swing state, conservatives will be wiling to have a serious discussion about this issue.