I agree with you.
Changing the way states chose electors is NOTHING new and it is Constitutional. If it works for Maine and Nebraska, I think it would do wonders for the following states:
Virginia
Pennsylvania
Ohio
Michigan
Minnesota
Wisconsin
Florida
California
Illinois
Iowa
Which ever of those states above that have Republican legislatures and governors better get on this, now.
Proportional allocation via Congressional district is how it was originally in most states. I believe the major parties went to winner-take-all to get rid of the smaller parties. If these states return to proportional allocation, Republicans might start winning those states, but there might also be third-party candidates stealing away Congressional districts.