How different would the initial meetings go with the other characters if he looked like his mother instead of his father.
Snape would have probably treated him better.
Malfoy probably would have thought he was a Weasley.
Molly and Arthur would confuse him with their kids.
laughing at Molly and Arthur confusing him with the other kids. remember the iconic phrase from the twins? "and you, madam, are calling yourself our mother!"