Extending usage of GraphMap at PredicateMap and ObjectMap level about rml-core HOT 2 OPEN

Couldn't the same be achieved with 2 predicate object maps, each having a predicate map but a different graph map?
Wouldn't you achieve the same with the following?

  rml:subjectMap [
    rml:template "subject"
  ];

    rml:predicateObjectMap [
      rml:graph  ex:graphA; 
      rml:graph  ex:graphB;
      rml:predicateMap [
          rml:constant ex:predicateAB;    
     ];
           rml:object  <object>
      ];

   rml:predicateObjectMap [
      rml:graph ex:graphC; 
      rml:predicateMap [
          rml:constant  ex:predicateC; 
      ];
           rml:object  <object>
      ].

from rml-core.

It is indeed possible to do it as you proposed.
However, the complexity comes when I start using LogicalTargets and FnO functions.
According to the specs for LogicalTargets and RML-FnO, both of them could be defined at the TermMap level for SM, PM, and OM.

It is just a syntactic sugar at this point, however, as a user (especially a new RML user), I would expect to also be able to define GraphMaps at the level of PM, and OM too. Since it is in a sense a "grouping" operation on triples.
Furthermore, depending on the predicate or object, I would like to group the triples into a specific named graph.

Otherwise, as it stands, I have to think at POM level which makes it a little bit confusing when combining LogicalTargets and FnO functions.

from rml-core.