I think 12 is good, possibly even 14 - didn't have a problem with the last 2 world cups which had 14 teams even though the bottom two basically got blown away in every game (Kenya and Canada in 2011, UAE in 2015).
I think 12 is good because it gives guaranteed exposure to at last 2 teams outside the established top 10. Have the top 10 in the rankings get autoqualification and then have a 8 or 10 team WCQ for the 11th and 12th seeds.
I think we should focus less on who is good enough and more on giving exposure. Thats why I don't have too many problems with a 10 team WC, because 13 teams are getting a shot at the ODI league - which in purely cricket terms is the bigger reward. 36 matches over 3 years is far more beneficial than 5 or 6 every 4th year.
Thats my opinion at least.
