RDF data model: too flat?

Working with the basic RDF model I get the feeling that the RDF data model
is too flat.

One of the aspects that has a contradiction with the world around us is
that in RDF there is (speaking in terms of frame based theory) only one
type of slot: Property.

In real world we see objects or things (RDF: Resources) with attributes and
relations between objects.
Attributes are dependent on their objects in which they are contained, in a
(binary) relation two objects are independent in existence but connected.

For example the weight, color of the eyes and day of birth are typically
attributes of a Person instance; the father, mother, spouse, car and bank
account are independent objects related to a certain Person.

I would make a plea for a second type of slot in the RDF model: Relation or
BinaryRelation.

I think that my suggestion is close to the CKML fundamentals, maybe the
CKML model would be the outcome when we think things all over.