The electoral college is there for a reason. One state can easily corrupt its election to such a degree that it could submit millions, no make that billions of fraudlent votes. In order to continue doing this, the state would have to be a one-party state that does not have to fear its judicial branch (like Washington or Oregon). This plan simply lets the one outlaw state steal the electoral votes of Maryland and all others that adopt it along with its own.
You are correct. It would nationalize vote fraud in the Democratic rotten boroughs.