Hmmm, He must have been sitting around thinking “How can we guarantee a Democratic controlled Senate until the end of time... Of course! We will just add a dozen commies!”
Not a problem. We can just quarter Wyoming and divide Idaho into thirds.
Kidding aside, the logic of this proposal is to simply abolish the Senate and have a unicameral legislature apportioned by population.
I would rather go the other way, turn back the clock, and repeal the direct election of senators. Return the Senate to its constitutional role as a representative of the states in a blended and balanced legislature.