what if MLB allowed teams to trade players to teams in other leagues. It could even be sort of like the transfer system in soccer, where you can loan a player to a team in another league. It could work with Japan, Korea, and Cuba (if only...). I don't think the players would like it at all and the union would have a fit about it, but it would be great to see.
Baseball is starting to gain some ground internationally. The WBC has certainly helped and once more countries turn to baseball, this could be a plausible idea. Sadly, It will be at least 50 years or so until anything like this ever happens, if ever.