We were asked on Twitter whether we knew about teams, host sites, and possible expansion for the 2020 World Baseball Classic Qualifiers. Plenty is already known and more can be surmised from previous qualifying rounds.
The four nations that finished last in their pools and will have to qualify are Taiwan, China, and Canada, Mexico. Taiwan and Mexico are certain to host rounds as they have multiple stadia suitable for international tournaments. There are 11 teams that have appeared in the WBC qualifier every time in addition to the above four: Brazil, Czech Republic, France, Germany, Great Britain, New Zealand, Nicaragua, Panamá, Philippines, South Africa, Spain. Between the two teams that have appeared once, it is likely to be Pakistan over Thailand for the final spot.
The only possible expansion is to add one more team to each bracket, in which case four teams would join. There is a big gap between the above 16 and the next tier of national teams, but possibilities are Thailand, Russia, Argentina, Indonesia, or an African team if countries like Ghana, Kenya, or Uganda make huge strides. All are extremely unlikely and our guess is expansion happens in 2024, which is too far away to prognosticate.
In regards to brackets, it seems feasible that Taiwan would host a bracket with China and the Philippines. New Zealand could go there, but our feeling is that MLB wants them to host. Problem is, aside from them, the fourth team in that pool would be either a European team or South Africa, which does not make much sense logistically. If New Zealand did host, they might very well have South Africa in their bracket as two southern hemisphere teams with historical (British Empire) and sporting connexions (rugby). As a side note, it would be very interesting to have GB and Canada in this bracket, but the logistics suggest that would not happen.
México will have either Nicaragua or Panamá unless MLB decides Panamá should host again, which would make sense. Brazil would likely be in a bracket that either hosted. Those four would be a brutal bracket by themselves (Nos. 6, 13, 15, 18), so that will not happen. We are guessing Panamá gets the bid and draws Brazil and, perhaps, Spain, while Mexico repeats the 2016 bracket with the Czech Republic and Germany.
We are guessing Canada again does not get to host and is either in an American bracket or at a European site (Germany or the Czech Republic), though they did not respond well to being sent to Germany in 2013. A pool of Canada, Great Britain, South Africa, and another European team (our bet is France) could be interesting.
There will be plenty of discussion of teams, hosts, and brackets before 2019, but our conclusion is that expansion will not be part of the official decision by the WBSC.