The removal of reference properties (see WS-A issue #1) from the WS-A specification is a non-event. Today, most implementations and specs that use WS-Addressing are based on either the March 2003 or the March 2004 version, both of which have only one echoing mechanism, called “reference properties”. And, if they use it right, these specs and implementations don’t use the reference properties for identification, they just use the EPR as a pointer which happens to use an echoing mechanism (most of them don’t even care about the echoing mechanism and whether it is used). For these people, there is no change resulting from the removal of reference properties, other than just replacing the name “reference properties” with “reference parameters”.
The only place where there is a choice between two mechanisms (properties and parameters) is in the August 2004 version, the one submitted to W3C. Newer specs (like WSDM MUWS 1.0) reference this version because it has a few clarifications and because it feels more comfortable to use a reference residing on the W3C’s site (even though it doesn’t mean anything in the case of a member submission). But I am not aware of any implementation or spec that uses the August 2004 version and takes advantage of the difference between reference properties and reference parameters. For example, WS-Management makes use of both constructs but I don’t see how anything in WS-Management would stop working if all its reference properties were transformed into reference parameters and/or vice-versa (for example, why does wse:Identifier need to be a reference parameter rather than a reference property?). Once again, the removal of reference properties is not a change to WS-Addressing, it is just the end of a little escapade into the exciting world of inventing unnecessary semantics.