I'd like to suggest an implementation solution for this. For both House Numbers attached to road segments and the Address property for Places (including Residential Place Points), let editors enter a house number that includes a special character, such as '#' (number/pound sign) or '_' (underscore) that delimits the house number part of the address from the sub-address unit number (or alphanumeric designator). Don't worry about the several different types of sub-addresses, like Unit, Apartment (Apt), etc. All sub-unit addresses can be formatted generically on a country-by-country basis.

For example, in the U.S. an acceptable generic way to format addresses could be "123 Main St #A5" using the number/hash sign, and this would be the format to display in the client app. In WME, this house number could be entered as `123_A5` or `123#A5`. In many other countries, including Spanish-speaking countries and regions, perhaps the app should use the numero symbol № or ordinal/degree symbol °, or in parts of Europe, "Nr.", and so forth. The order that each of the address elements appear in the app and the appropriate delimiter(s) between those elements would depend on the country/region and should be designed in consultation with appropriate localization experts. But for mapping in WME, a single consistent delimeter, such as the # or _ I suggest (which are unlikely to appear in an address in any other context), could be used worldwide.

In areas where single family for rent communities exist each of hundreds of houses are the same exact address. The roads are mapped as parking lot roads. The house numbers are not mapped. These areas look at feel just like a regular single family community, but because they are "for rent" their addresses are not unique and are therefore not mapped. This makes routing and finding the right place very difficult. Being able to add unit numbers in these areas would help a LOT

Also adding "Lot" numbers as an option would be helpful.

Additionally the ability to name the residence (apartment building, condominium complex, dormitory, etc.) would be very helpful.