How many homes do you think that would apply to, and do you think it's a meaningful enough number that a small increase in property taxes would raise the revenue required by this initiative? Or is it such a small number of homes that the rate increase would be so punitive as to encourage large families and moderately well-off people to instead buy houses outside the city limits?

I don't know the answer - just pointing out that making value judgements (small homes are better, that there's an 'appropriate' square footage and home value people should have, etc.) and codifying them can affect a complex system in unintended ways, sometimes doing the opposite of what well-intentioned people want.