Actually applied nationwide, George W. Bush would have won rather comfortably in 2000. It would have avoided the drawn out fight over the recounts in Florida. There would have only been 2 electoral votes in doubt not 26. While the statewide count was very close, the district by district results weren't. There would be incentives for presidential candidtates to campaign not only in close states, but in close districts in states that would currently be completely bypassed.
Several states with DemocRAT legislatures that voted for the Republican presidential candidate considered legislation to go to a district by district system. The DNC opposed it. They have large pockets of votes concentrated into a few congressional districts that often vote 90% or above DemocRAT.