I think they should leave it in February, and maybe move MLB Spring Training ahead to Feb. 1 every 3-4 years when the WBC is scheduled. I think that playing it in November might be a bad idea. I have heard interviews (and have personally spoken to one former major-league pitcher) that have said that a pitcher's arm is seriously fatigued by the end of the major-league season. Also, if the WBC were to be played after the World Series, I would fear a "Pro Bowl Syndrome" type of apathy among U.S. fans.
I would also leave it at 16 teams, and I would like to see the top eight qualifiers from this year (that is, the eight teams in Round 2) automatically qualify for the next WBC in 2009. Then have a qualifying tournament the year before, in 2008, to determine the other eight teams. Most of them will be taken by teams that were in it this year, but it will give some other countries a chance to participate if they can win one of the eight spots. Are some of those countries ready for the "big time"? Probably not, but simply qualifying will give baseball in those nations a big boost. As for the single-elimination semifinals/finals, I don't mind it. It is a different format than we American fans are used to, but it is very similar to the soccer World Cup format (from which the WBC borrows heavily). Also, as a former high-school baseball coach, I am somewhat used to the urgency of a single-elimination tournament, and I can see the excitement in it.
I have been very critical of Commissioner Bud Selig during his tenure--even to the point of once referring to him as the "antichrist of baseball" in an email that was read on the air by Marty Brennaman. But I think that the WBC is a great idea--probably Selig's best ever. I know that I have bought into it. But we have to get more top players to want to play in it. I'm not a soccer fan, but I think we need to see how they get players, owners, and fans to really buy into the World Cup, and see if some of those ideas would work in the WBC.