ChCh and Wellington are pretty much neck and neck in terms of size/population.Christchurch is a decent sized city that’s growing every year and is a sports mad city with amazing new stadium to boot.
from what I’ve heard out of the 3 cities wellington is the less sporty city plus I hate the cake tin!!
Wellington does have more top level sports teams so perhaps the market is more saturated.
I’m assuming you’ve never actually been to Sky stadium? The people that tend to hate it are usually the ones that have never actually been there- great location in proximity to the downtown and public transport and it’s one of the easiest stadiums I’ve been to in terms of getting in/out to your seat before/after the game. Circle layout gets overplayed never had a bad view there