IDK. Sosa had a oversized personality that drew a lot of fans in. McGwire was an older veteran trying to break the old Marris record that seemed unbeatable. I think there's a good story there.
Helps that both players played on opposing teams of a historical rivalry too.
What could go wrong with being tied into gambling? Oh wait, there's a lawsuit from fantasy owners due to the Astros cheating? Cool cool cool...
Each team should replace the name on the back of the jersey with a corporate logo.