Ticket T148819 solved lot of use cases but not all in my opinion.

I would like create some universal wheel slot (or even car parts slots).

But when I modify parent class CarWheel, of course will be overriden by all inherited wheels and it will not work.

Thats why for that use case really need scripted way to control that config. Basically iterate over all inherited wheels and add attachment slot from script side.

I think there are also other use cases which allow dynamically control which item can be attached to particular slot.