Some people are so worried about what a block of flats looks like, they forget that people actually live there. I don’t think a pile of shoes outside a door is attractive, but is it the end of the earth? And if it is (and it may well be if we’re talking about two pairs for each member of a family of four) then require them to be placed in a neat box or on a shoe rack, or require them to be kept inside the front door of the apartment or carried through to their balcony for outdoor storage.
Removing shoes at the door is a cultural practice and wearing “outdoor shoes” inside the front door is highly offensive in some cultures. In Australia, we don’t think much about whether the soles of our shoes have been exposed to dog pee or other gross substances on the grass outside. But in some cultures, dog pee on shoes would be considered absolutely disgusting. So it’s important to be sensitive when addressing this issue.