Would say Vancouver > Buffalo > Twin Cities > Ottawa > Detroit/Boston.
Ottawa probably has a tonne of interest but Melnyk is killing it rather quickly, so I'd have them lower.
Boston has success and history, but they compete with the Pats, Celtics, and Red Sox, so its tough to imagine they have the most interest.
Detroit - Similar to Boston. Baseball and NFL.
Twin Cities - Vikings have a huge fanbase and are actually semi-decent. Shame they will never win anything, I hate being a vikings fan. Dunno if hockey has more interest than the Twins?
Buffalo - Bills are okay...? Been pretty shit for a long time though. No baseball team and second closest to the border of the US teams.
Ottawa - Dominates the CFL interest wise, but Melnyk is a cancer. No other major sports to deal with.
Vancouver - Also dominates the CFL, not sure fans rioting was 100% hockey, probably just shit distubers followed by mob mentality. No other major sports to deal with, MLS is still meh.
In most of these cities Hockey is probably fighting for #3 with NBA. No one knows for sure, but this would be my guess