Posting on behalf of a customer. 
It would be nice to have the ability when creating custom objects to select from properties that are not just Single-line text or Number, (the requirement noted in the KB here) but rather any of HubSpot’s supported property types.
YES! In the few custom objects I’ve created, I’ve always wanted either a drop-down or a date/time under the main display properties, preferably as the primary property. It’s inconvenient to require users fill in a text property name for a record that could be better described by a different type of field that they are going to have to fill in anyway.
For example, my company has multiple divisions, and a client company might work with more than one division, so I’m working on a custom object that has the details of each of the client’s relationships to a different division. In this case, the best primary property for this object would just be a drop-down of all the divisions because that’s the first thing we want to see on that object—which division is it representing a relationship with?—and this is an object that will only ever be associated to a company, so it doesn’t need a unique name. The user who creates the record will have to complete such a drop-down anyways, but right now, I have to make that a non-display property and require the user to enter some arbitrary name, which will probably end with users just naming the record “Division C” and also choosing “Division C” from the drop-down.