In the presence of an adequate abstraction model, an application
should not care whether a given host has one address or a dozen,
nor about whether such addresses were equivalent or different,
nor about whether they represent physically separate interfaces.
there are lots of assumptions behind this about what an "address" is,
how it gets used, when and where the address-to-host binding takes place
and whether it can change, etc. that are sufficiently different than
the current IP world that I can't tell what you are assuming.