Whether the rules changed later or not have nothing to do with it. It was within the rules at the time, and therefore Michigan State deserves the credit for finding a creative way to run a play within the rules.
In the 1991 World Series, Game 7, 8th inning, with Lonnie Smith on first, Terry Pendleton doubled to the gap. Smith should have scored easily, except for one thing--Twins infielder Chuck Knoblauch faked that the play had come to him, and faked a throw to second. Smith slid into second. He quickly realized what had happened, got up, and advanced to third, but the damage was done. He didn't score on the play, was stranded there when the inning ended three batters later on a double play, and the Twins ended up winning in the tenth inning, 1-0. Cheap play by Knoblauch? Hell no! It was brilliant deception, that resulted in a World Series Championship!
In 1982, at the College World Series, the Miami Hurricanes pulled off what has come to be known as "The Grand Illusion". See the link below for the details. Cheap play by the Hurricanes? Hell no! Again, it was brilliant deception, and again, it led to a National Championship!
Plain and simple--nothing that happens within the rules of a game or sport deserves to be called "cheap". If it was that disagreeable, it would have been outlawed. If it hasn't been outlawed simply because it's so creative that the rulemakers haven't accounted for the possibility yet, then the team doing it deserves credit for having enough creativity to come up with it--not derision for doing something, just because it happens to fall outside the "ordinary" style of play.