The WBC was not generated as a response to the IOC's decision to eliminate baseball. MLB was planning a World Cup type event as early as 2002, three years before the IOC voted to remove baseball from the Olympic Program. Many people think that MLB's creation of the WBC was a reaction to the IOC's elimination of baseball. The WBC had been originally planned for 2005, but the NPB and its Player's Union did not readily agree to participate and instead the inaugural WBC was pushed back to 2006; around the same time the IOC released their news of baseball's omission from the Olympics.

Here is an excerpt from an old article (6/19/2003):
Read @ Sports briefs - Taipei Times

The Netherlands used a bunch of professional players to win the last World Cup; the IBAF World Cup has allowed Professionals to participate since 1998, but the Tournament is now defunct. It will be replaced with an event named the Premier 12 set to debut in 2015.

I think the WBC is a good way for countries to compete. In olympics since there is so much going on, its nice to separate the sport into a event for it own.

Dominican republic just won the WBC congrats to them. they are going to be a top contender