The relevance of the Seiwa ruling in this case is the obligation placed on Owners Corporations to maintain common property. Seiwa doesn't exclude appearance as a factor.
However, the Act does specifically mention appearance as being a consideration in the maintenance of Common Property. There's no need to dig any deeper that the Act and no point in making assumptions based on other cases that have no relevance to the matter under discussion.
Yes, there is a choice about how far you might want to go with this but I think there would be no harm in explaining to the other owners that they have a legal obligation to maintain common property and then see what they decide.
By the way, having written about Real Estate for many years now, I can assure you that the look of a building and the care or otherwise taken of common property has a profound effect on property values. For a lot of prospective buyers, it's the only clue they have to the way the building is run.