When you look at the dates, it's likely that extra shows will be announced when ticket sales justify that.
Chicago, Montreal, Philadelphia, Columbus, Belmont, Boston and New York City seem obvious
Speaking as a fellow Ohio resident, I think the band would add a second Cleveland show before they would add a second Columbus show. Cleveland has always been a city that supported the band on every tour since they started coming to the US. Columbus is a town the band just started visiting since the WCD tour.