I appreciate the outside of the box thinking this article proposes, I suppose it is a good idea if only for this season. I am not sure they would stop there once they start. They are already doing this in the minors, I think more than we realize. Looking at the box scores daily, most pitchers are going 3 to 5 innings and throwing 60 to 70 pitches. Is it becoming a self fulfilling prophecy that they can't become starter because they are not being developed as starters.
This concept may work in the minors where development is the priority. But what do you do when Judge comes up in the 7th with the bases loaded and up by 2 runs, are you going to leave your second piggyback pitcher in who has only thrown an inning plus or go to a high leverage reliever. My point is that in the final three innings it will be tough not to go more matchup based rather than leaving basically your 4th or 5th starter out there.
The other point is casual fans don't necessarily like seeing 3 to 5 pitchers in a game, it slows the game down, they don't know the back end of the roster players and it is not always enjoyable experience for them. I realize this is a baseball issue and not just the Twins. But I don't believe in just developing throwers and I do hope it swings back to where pitchers are actually being developed to pitch.