If minority voters keep on voting overwhelmingly for Democrats, Republicans are going to have a tough time no matter what the election format is.
But...
You have to account for the fact that CA has a huge redneck/farmer population, as does NY. Right now their votes are pointless. Popular vote puts them back in play. Granted alot of that would be made up in some of the southern states where dem votes are pointless, but it would change the entire game.
If Texas continues to evolve the way it is, it will become the only swing state that matters for dems under the current system. CA and NY are in the bag. If you get TX you can't lose. F FL and F OH at that point.
Either system we go with, I cannot imagine another republican president for the foreseeable future.