Rose bet on baseball games, including those of his own team,and is banned from the game. There is no bigger taboo in baseball then betting on games.A hall of fame that doesn't have the best players in it like Bonds and Rose really doesn't have much credibility, does it?
the game itself hasn't changed that much
The one thing that really changed was the break between the "dead ball" era, and the current game. Up until after WWI, it was not a slugger's game - it was all about bat control and placing the ball. "Small ball" as they call it now.