i am not very familiar with pattern but being arospace eng. i think the wider bodies play a role in slowing the plane down, if nothing else you have more air displacment then more slimline models (More volume moving ) and this thing called air to surface contact area, more area you have for air to contact, more drag you get.
on the other hand i think larger propelers create more bad air behinde the prop and chick cowls and most of the landing gear are in the bad air sreem and dont play much of a roll, retract bays also create lots of drag that imo = to a good grear,
i might be wrong but some stuff to think about